BAKES, Justice.
Appellant was convicted of first degree murder in the beating death of eight month old Monique Longoria and was sentenced to death. He appeals both his conviction and his sentence. In addition, we review this case pursuant to our duty under I.C. § 19-2827 to independently review sentences imposing a penalty of death to ensure that those sentences are free from error, and are proportionate and just. We find that no reversible error was committed by the trial court, and we affirm the conviction and sentence.
Viewing the evidence in the record most favorably to the respondent, as we must on appeal, State v. Barsness, 102 Idaho 210, 628 P.2d 1044 (1981), the facts adduced at trial are as follows. In early 1982, appellant was living in Ketchum with Teresa Watson and her daughter, Monique Longoria. On April 10, 1982, Watson placed Monique in the bathtub unattended while she and appellant ate lunch. Ten minutes later, appellant went to use the bathroom. Watson testified that about five minutes later she heard a gasp from Monique and loud pounding noises. At that point, Wat[361]*361son went into the bathroom to investigate. She observed appellant sitting on the toilet, with “one hand in the tub like he was splashing water on her.” At appellant’s direction, Watson left the bathroom and returned to the living room. After a short time, appellant emerged from the bathroom and asked Watson if he should take the baby out of the bathtub. Watson replied in the affirmative. Appellant then reentered the bathroom and then called Watson, indicating something was wrong with the baby. Watson went into the bathroom and observed that the baby was not breathing. She took the baby into the bedroom and performed cardiopulmonary resuscitation. At that point she noticed injuries to the baby’s head. She asked appellant to summon an ambulance, but he refused. Watson then ran to summon an ambulance. When she returned, appellant asked her, “What are you going to tell them?” She replied, “I’m going to tell them the truth.”
Monique was taken to the local hospital, and, because of her critical condition, she was transferred to a Salt Lake City, Utah, hospital. Doctors there examined her and attempted to revive her, but she died on April 12, 1982. An autopsy was performed. Medical testimony at trial indicated that Monique died from blows to the head, a minimum of two and probably three blows. Testimony indicated that the blows which were inflicted were of a force equal to dropping Monique off a three- or four-story building two or three times. Testimony indicated that the injuries could not have been inflicted accidentally or by the activities of Monique herself.
I
Appellant was convicted of first degree murder by a jury and, after a presentence investigation and an aggravation/mitigation hearing, was sentenced to death. The trial court issued a detailed explanation of the factors that he had considered in mitigation and aggravation. After a detailed discussion of the mitigating circumstances, and upon finding three statutory aggravating circumstances existed beyond a reasonable doubt, the court stated: “The court is unable to find any mitigating circumstances which could overcome the aggravating circumstances and must comply with the legislature’s mandate. The court must and does impose the sentence of death on the defendant Mark Emilio Aragon.” Appellant asserts numerous errors on appeal.
A.
Appellant first argues that the trial court erred in its instructions to the jury defining “malice” and the elements of first degree murder. He argues that the definitions given to the jury did not sufficiently distinguish between a murder committed with malice, which may be first or second degree murder, and a murder committed with premeditation, deliberation and willfulness, which is always first degree murder. Without sufficient distinction between these elements, appellant argues, a jury may erroneously convict a person of first degree murder, for which the death penalty may be imposed, where the facts of the case support only a second degree murder conviction, with the death penalty unavailable as a form of punishment. If this were to happen, appellant argues, imposition of the death penalty would be rendered unjust and disproportionate, in violation of the eighth amendment of the United States Constitution.
Instruction 23 given by the court defined murder as:
“Murder is the unlawful killing of a human being with malice aforethought. “Malice is that state of mind manifested by the doing of an unlawful and felonious act intentionally, deliberately, and without legal cause or excuse.
“Malice may be express or implied. It is express when there is manifested a deliberate intention unlawfully to take away the life of a fellow creature. It is implied when no considerable provocation appears, or when the circumstances attending the killing show an abandoned and malignant heart.”
[362]*362The first sentence of the above instruction is taken directly from I.C. § 18-4001.1 The third paragraph is taken directly from I.C. § 18-4002.2
Instruction 25 defined first degree murder as follows:
“Murder in the First Degree is defined in this case as all murder which is perpetrated by any kind of wilful, deliberate and premeditated killing.
“In order to prove the commission of the crime of Murder in the First Degree, each of the following elements must be proved beyond a reasonable doubt:
(a) That a human being was killed;
(b) That the killing was unlawful;
(c) That the killing was done with malice aforethought;
(d) That the killing was willful;
(e) That the killing was deliberate; and
(f) That the killing was premeditated.”
Instruction 27 defined second degree murder as follows:
“Murder in the Second Degree is defined in this case as all other kinds of murder. “In order to prove the commission of the crime of Murder in the Second Degree, each of the following elements must be proved beyond a reasonable doubt:
(a) That a human being was killed;
(b) That the killing was unlawful;
(c) That the killing was done with malice aforethought.”
The court then gave the following instruction 28, distinguishing the elements differentiating first and second degree murder:
“As set forth in the preceding instructions on murder, any unlawful killing of a human being with malice aforethought is murder. If nothing further characterizes the killing, the murder is of the second degree. To constitute the higher offense of murder in the first degree, there must be wilfulness, deliberation and premeditation in addition to malice aforethought.
“Wilfulness means that there was manifested a clear intent to take life. “Deliberation and premeditation means done with reflection and conceived beforehand and not done upon a sudden heat of passion or other condition precluding the idea of deliberation. “Premeditation does not require an appreciable space of time between the intention to kill and the killing; they may be as instantaneous as successive thoughts of the mind.”
This instruction incorporated parts of the previously mentioned instruction, and also noted the elements set out in I.C. § 18-4003.3
An instruction to the jury that essentially follows the words of a statute normally is not error. “Ordinarily, the language employed by the legislature in defining a crime is deemed to be best suited for that purpose, and error cannot be predicated upon its use in informations and instructions.” State v. Brooks, 49 Idaho 404, 409, 288 P. 894 (1930); see also State v. Anstine, 91 Idaho 169, 418 P.2d 210 (1966). Because these instructions follow the language of the statute, it was not error to give them. Furthermore, the major portion of these instructions was requested by appellant. Particularly, appellant complains of given instruction 28, claiming it gave an improper definition of the terms “deliberate” and “premeditated.” However, given instruction 28 is substantially identical to [363]*363defendant’s requested instruction 12. Appellant cannot assert as error on appeal the giving of an instruction which he himself requested. Henry v. Mississippi, 379 U.S. 443, 85 S.Ct. 564, 13 L.Ed.2d 408 (1965); Daellenbach v. State, 562 P.2d 679 (Wyo. 1977).
The instructions did not blur the distinction between first and second degree murder. Jury instructions must be read in their entirety, as a whole, not in their isolated parts. State v. Griffiths, 101 Idaho 163, 610 P.2d 522 (1980); State v. Tisdel, 101 Idaho 52, 607 P.2d 1326 (1980); State v. Peterman, 100 Idaho 269, 596 P.2d 442 (1979). In reading the instructions as a whole, we note that they are internally consistent, and they sufficiently define for the jury the distinction between first and second degree murder. On the one hand, the jury was informed of the definition of murder, and that it involves killing with malice. Malice was defined as a “state of mind” manifested by an intentional or deliberate act. The jury was instructed that malice may be express or implied. These were proper definitions of malice and its interrelationship with the definition of murder.
Further, the jury was instructed that if nothing more than malice, or the intent to do an unlawful act, was proven beyond a reasonable doubt, then the crime could not be first degree murder. The jury was instructed that if it could find beyond a reasonable doubt three other elements — willfulness, deliberation and premeditation— then the defendant was guilty of first degree murder. Malice, the intent to act feloniously, was properly distinguished from willfulness, the intent to take life, premeditation, conceived beforehand, and deliberation, done with reflection. The jury was properly instructed on the additional elements necessary to prove first degree murder, and thus there was no error.
B.
Appellant also asserts error in the court’s instructions to the jury concerning reasonable doubt. Appellant requested the following instruction:
“When you are convinced beyond a reasonable doubt that the crime of murder has been committed by the Defendant, but have a reasonable doubt whether such murder was of the first or of the second degree, you must give to such Defendant the benefit of that doubt and return a verdict fixing the murder as of the second degree.”
See I.C. § 19-2105. In State v. Hunter, 55 Idaho 161, 39 P.2d 301 (1934), we noted that such an instruction, if requested, should be given to inform the jury of the defendant’s right to be convicted only of the offense where all of the elements have been proven beyond a reasonable doubt. We noted that the instructions given in Hunter did not sufficiently instruct the jury on this point. However, Hunter does not require that this particular instruction be given automatically upon request without regard to the circumstances of the particular case or the other instructions given. As this Court noted three years later in State v. Van Vlack, 57 Idaho 316, 65 P.2d 736 (1937), this instruction need not be given if the subject matter is covered in other instructions. This is in line with the general rule in Idaho that requested instructions, even if correct on the law, need not be given if the subject matter of the instruction is covered in other given instructions. See State v. Griffiths, supra; State v. McKeehan, 91 Idaho 808, 430 P.2d 886 (1967).
In this case, the jury was properly instructed on the difference between first degree murder, second degree murder, and the other lesser included offenses. The jury was also instructed that all the elements of the crime charged must be proven beyond a reasonable doubt and that if it could not find the defendant guilty of the crime charged it must proceed to determine the guilt or innocence of the defendant of any of the lesser offenses defined for the jury. Thus, the subject matter of defendant’s requested instruction was sufficiently [364]*364covered by other given instructions, and there was no error.
C.
At trial appellant sought an instruction on the duty of a parent to protect its child. This instruction was refused by the trial court. Appellant assigns this refusal as error. Appellant’s rationale for requesting this instruction was that, if it could be shown that Teresa Watson was an accomplice, because of a legal duty to protect her child and her failure to do so, then her testimony would then have to be corroborated, and without such corroboration appellant could not have been convicted. However, assuming that there was such a legal duty on the part of the witness Watson, and that her failure to adequately carry it out constituted a separate crime, it does not follow that her conduct would necessarily make her an accomplice to the crime for which the defendant Aragon was charged. In order for her conduct to elevate her to an accomplice status, the evidence would have to be reasonably susceptible of concluding that the witness Watson aided, abetted, counseled, induced, or procured the commission of the murder of the child. The trial court submitted that issue to the jury by three instructions dealing with accomplices and the necessity for corroboration of their testimony, which correctly stated the law on that subject.4 The trial court did not err in failing to give appellant’s requested instruction. Appellant alleges that, “As a matter of law, Teresa Watson’s testimony was not corroborated.” However, the record discloses otherwise. Idaho case law throughout the years has defined the sufficiency of corroboration necessary for a conviction. The corroborating evidence offered need only connect the defendant with the crime. State v. Evans, 102 Idaho 461, 631 P.2d 1220 (1981); State v. Bassett, 86 Idaho 277, 385 P.2d 246 (1963); State v. Mundell, 66 Idaho 339, 158 P.2d 799 (1945); State v. Gilbert, 65 Idaho 210, 142 P.2d 584 (1943). While the corroborating evidence must be independent of the accomplice’s testimony, State v. Bassett, supra, it need not be sufficient in and of itself to convict the defendant. State v. Gillum, 39 Idaho 457, 228 P. 334 (1924). Corroborating testimony may be slight and need only go to one material fact. State v. Evans, supra; State v. Mundell, supra; State v. Brown, 53 Idaho 576, 26 P.2d 131 (1933); State v. Orr, 53 Idaho 452, 24 P.2d 679 (1933). In addition, the testimony may be entirely circumstantial. State v. Mundell, supra; State v. Brown, supra; State v. Gillum, supra. In the past, we have upheld the sufficiency of the corroboration in situations where there was independent identification of a ski mask worn by the defendant on the night of the crime, and hair taken from the mask closely matched that of the defendant, State v. Evans, supra; where [365]*365the condition of the victim supported the inference that force was used where the defendant was charged with rape, State v. Adair, 99 Idaho 703, 587 P.2d 1238 (1978); where the defendants were identified as being in the truck used to commit the crime at the approximate time the crime was committed, State v. Bassett, supra; and that the statements and actions of the defendant after his arrest may be sufficient to corroborate an accomplice’s testimony, State v. Brown, supra.
In this case there was more than sufficient corroboration of Teresa Watson’s testimony. There was testimony by a neighbor indicating that appellant had previously threatened to throw Monique out of a moving pickup unless she stopped crying, and had abused her in his presence on at least one occasion, when he picked her up and threw her onto a couch. Testimony of Monique’s treating physicians indicated that a great deal of force would have to have been used in order to inflict the injuries Monique suffered. In addition, appellant was placed on the scene through the testimony of two ambulance drivers. These drivers testified as to the condition of both Teresa Watson and appellant. Teresa Watson was described as hysterical, and appellant was described as mute and demonstrating no reaction to the fact that Monique had been injured. Another neighbor also testified to Watson’s agitated condition. This is more than sufficient corroboration of Teresa Watson’s testimony.
D.
Appellant argues that he was denied a fair trial because the prosecution failed to disclose material evidence. Specifically, defense counsel did not learn until after trial of a report by Officer Jerry Femling in which he reported a statement made by Teresa Watson’s mother, Mrs. Brown. According to the report, Mrs. Brown had talked to Officer Femling prior to Monique’s death, stating that “Teresa in the past had hit the child and shakes it when it crys. She has called the child abuse center on Teresa before. Mrs. Brown also said that Emilio Aragon does not like the baby and Teresa had to talk Emilio into letting her take the baby with her.” Appellant alleges that the withholding of this report by the prosecution deprived him of a fair trial.
Appellant asserted the same argument before the trial court in a motion for new trial, and the trial court held an evidentiary hearing which disclosed that on April 10, the date of the beating of the deceased child, Officer Jerry Femling of the Ketchum Police Department received the telephone communication from Teresa Watson’s mother, Dorothy Brown, and made a handwritten note of that conversation. However, that report was never typed up and forwarded to the Blaine County prosecuting attorney’s office. Rather, Officer Femling related that telephone conversation to Gary Starkey, an investigator for the Blaine County prosecuting attorney’s office, who the next day contacted Mrs. Brown concerning the matter. Officer Starkey testified that Mrs. Brown told him that she had never seen her daughter Teresa Watson strike the grandchild, although she had seen her shake the child when it cried too much. Mrs. Brown also advised the investigator that at an earlier time she had filed a complaint with the Health & Welfare Department in Twin Falls. Starkey’s impression of that conversation was that Mrs. Brown, who had custody of the child for approximately one to two months after it was born before her daughter Teresa Watson took the baby away, was upset because she did not approve of her daughter’s lifestyle, and she wanted to keep custody of the child herself. In addition, the record reflects that investigator Starkey contacted the Health & Welfare Department in Twin Falls where Mrs. Brown made her complaint. Miss Warner, the caseworker who discussed the matter with investigator Starkey, testified that they had received the complaint from Mrs. Brown and had investigated whether or not the child was being properly cared for, and concluded that there was no indication that Teresa Watson was not properly caring for [366]*366her child. The caseworker testified that she had concluded that Teresa Watson did not get along with her mother and that the mother wanted the child to raise for herself. Accordingly, the department had taken no action on Mrs. Brown’s complaint.
After hearing the foregoing testimony, and after concluding that the prosecuting attorney’s office and its investigator were never aware that Officer Femling had made the handwritten note referred to above, the trial court concluded that no violation of the defendant’s right to discovery had occurred, and accordingly denied the motion for new trial.
Prosecutors have a constitutional duty to disclose to the defendant any exculpatory information in their control. State v. Horn, 101 Idaho 192, 610 P.2d 551 (1980); see also United States v. Agurs, 427 U.S. 97, 96 S.Ct. 2392, 49 L.Ed.2d 342 (1976). Exculpatory evidence is evidence which, if known, would have created a reasonable doubt of guilt that did not otherwise exist. State v. Brown, 98 Idaho 209, 560 P.2d 880 (1977). A prosecutor’s failure to disclose such exculpatory evidence is a denial of due process. State v. Harwood, 94 Idaho 615, 495 P.2d 160 (1972). However, to constitute a denial of due process, the exculpatory information must be shown to be material. As the United States Supreme Court noted in United States v. Agurs, supra,
“The mere possibility that an item of undisclosed information might have helped the defense, or might have affected the outcome of the trial, does not establish ‘materiality’ in the constitutional sense.” 427 U.S. at 109-110, 96 S.Ct. at 2400.
The evidence that appellant urges us to accept as exculpatory does not meet the test of materiality established in federal and state cases.
The record reflects that Mrs. Brown’s statement was hearsay, and she had no persona] knowledge of her daughter Teresa hitting her child. Her statement that she would shake the child when it cries was at most cumulative and in no way exculpatory. Her statement that she had called the child abuse center on Teresa before appears to reflect only her own motive to obtain custody of the child. Accordingly, the statement does not establish the materiality necessary to constitute a violation of either the prosecution’s constitutional duty to disclose exculpatory information under United States v. Agurs, supra, or a violation of I.C.R. 16. Accordingly, appellant was not deprived of a fair trial.
E.
Appellant also argues that evidence presented at trial was insufficient to prove deliberation and premeditation. In analyzing appellant’s contention, the appropriate standard of review is whether there is substantial competent evidence to support the jury’s verdict. State v. Warden, 100 Idaho 21, 592 P.2d 836 (1979); State v. Griffith, 97 Idaho 52, 539 P.2d 604 (1975); State v. Cypher, 92 Idaho 159, 438 P.2d 904 (1968). Our function on appeal is to examine the supporting evidence, not to place ourselves in the jury’s position or reweigh the significance of evidence as it relates to specific elements. State v. Evans, supra; State v. Cysewski, 101 Idaho 353, 612 P.2d 1200 (1980). On appeal, all facts, and inferences to be drawn from those facts, are construed in favor of upholding the lower court decision. State v. Barsness, 102 Idaho 210, 628 P.2d 1044 (1981), appeal dismissed 454 U.S. 958, 102 S.Ct. 495, 70 L.Ed.2d 373.
The jury was properly given the following instruction:
“To establish the crime of First Degree Murder, direct evidence of a deliberate and premeditated purpose to kill is not required. The necessary elements of deliberation and premeditation may be inferred from the proof of such facts and circumstances as will furnish a reasonable foundation for such an inference.”
We conclude that there were sufficient facts and circumstances to furnish a reasonable foundation for the inference that these elements existed. For example, there was evidence of appellant’s pre-exist[367]*367ing dislike for the victim. There was testimony indicating previous threats against the victim by appellant. There was also testimony indicating prior incidents of mistreatment of the victim. Furthermore, medical evidence established that the injuries received by the victim were unusual and difficult to achieve and must have been inflicted by extraordinary force. In addition, the fact that there was more than one such blow supports a finding of a preconceived intent to kill. Appellant’s demeanor after the injuries were inflicted is also a basis for the inference that appellant had planned to inflict injuries on Monique. He was calm, refused to aid the victim or seek help in any way, and instead began planning how he could cover up his involvement in the incident. From this evidence the jury could reasonably infer a premeditated and deliberated killing. That verdict will not be disturbed on appeal.
F.
Appellant argues that the aggravating circumstances found in I.C. § 19-2515(f)(6) and -(8) are unconstitutionally vague. This argument has been raised in several of our previous death penalty cases, and has been disposed of in those cases by the actions of this Court in placing a limiting construction on each of these circumstances. It can no longer be claimed that these circumstances are unconstitutionally vague. See State v. Sivak, 105 Idaho 900, 674 P.2d 396 (1983); State v. Creech, 105 Idaho 362, 670 P.2d 463 (1983); State v. Osborn, 102 Idaho 405, 631 P.2d 187 (1981). All of the aggravating circumstances found by the trial court are supported by substantial competent evidence and thus will not be disturbed.
The trial court found the existence of the circumstance in I.C. § 19-2515(f)(5), that the murder was especially heinous, atrocious and cruel. The existence of this circumstance is supported by evidence that the victim was severely injured through the use of tremendous force, even though the victim was an eight month old child who could not possibly pose a threat to appellant, or provoke him intentionally. The defendant himself admitted hitting the child with his fist. The court also found the existence of I.C. § 19-2515(f)(6), the defendant exhibited utter disregard for human life. Again, this finding is supported by evidence that appellant acted calmly, yet violently, and refused to render aid to the victim, even though given several opportunities, and even though it was obvious the victim was in mortal peril. His only concern was to cover up his own participation in the incident. Finally, the court found the existence of I.C. § 19-2515(f)(8), that appellant has exhibited a propensity to commit murder that poses a continuing threat to society. This finding is supported by appellant’s past criminal record, which includes charges of child abuse and assault with a deadly weapon, as well as the utter lack of remorse shown by appellant over the death of the child.
II
In cases where the death penalty is imposed, we have a duty to conduct an independent review of the case to ensure that the penalty was imposed without resort to passion or prejudice and that the imposition of such penalty is not excessive or disproportionate. I.C. § 19-2827.
There is nothing in this record to indicate a resort to passion or prejudice. Instead, we find virtually an error-free trial conducted by a trial judge intent on giving the defendant every opportunity possible to obtain a fair trial. The jury was adequately instructed on the law applicable to this case, and the evidence presented at trial supports the first degree murder verdict returned by the jury.
The trial court compiled an extensive list of findings and found no mitigating circumstances which outweighed the gravity of the aggravating circumstances. The court found three statutory aggravating circumstances existed beyond a reasonable doubt. The trial court considered all of the possible mitigating circumstances urged by appellant, and also considered the possibility of the existence of additional mitigating [368]*368circumstances, but after consideration decided that none of the factors either suggested by appellant or considered by the court on its own constituted a mitigating circumstance. We find no error in the procedure followed by the trial court in making its findings.
In conducting our proportionality review under I.C. § 19-2827, we conduct a review of the sentence imposed, and the sentences imposed in similar cases, to assure that the sentence in this case was not excessive or disproportionate. In comparing this case with other death cases, we generally consider the nature of and the motive for the crime committed, such as our consideration in State v. Gibson, 106 Idaho 54, 675 P.2d 33 (1983), and State v. Paradis, 106 Idaho 117, 676 P.2d 31 (1983) (killing of an eye witness to another homicide), as an indication that the sentence imposed was proportionate to other murder cases. In State v. Sivak, supra, we considered the “heinous nature of the crime ... and the nature and character of the defendant” in deciding that the sentence in that case was proportionate and just. In State v. Creech, 105 Idaho 362, 670 P.2d 463 (1983), we conducted a thorough review of cases implicating the death penalty to determine the proportionality of the sentence.
We find nothing in the record of the case at bar, after a consideration of the nature of the crime, the character of the defendant, and penalties imposed in similar cases which would indicate that the sentence here imposed was disproportionate or unjust. The crime committed was an intentional act perpetrated on a helpless victim who could not have provoked the attack. The attack was brutal, and one that only could have been intended to kill the victim because of the severity of the blows dealt. The character of the defendant, appellant here, is not that of an exemplary citizen, but rather of a convicted felon with apparently little respect for the law or fellow human beings. At least two of appellant’s many previous convictions involved disrespect for the welfare of others, including one conviction for assault with a deadly weapon, an incident where appellant knifed a man in a bar.
An examination of recent similar cases indicates that this case is easily aligned with others in which the death penalty was imposed. In all of the more recent cases, the cruel nature of the crime and the character of the defendants were similar to the case at bar. In both Gibson and Paradis the murder committed was brutal and the character of the defendants was less than exemplary as reflected by their prior criminal records. In Sivak, the defendant and a cohort brutally murdered a female gas station attendant. Again, the record of the defendant was far from spotless. In Creech, the nature of the crime and the character of the defendant were especially supportive of the imposition of the death penalty. In all of these recent cases, the aggravating circumstances surrounding the commission of the crimes far outweighed any mitigating circumstances found, if indeed any could be found. We find that the sentence imposed in this case is proportionate to those imposed in similar death cases.
In conducting our proportionality review we have also examined numerous cases involving the killing of a human being, although not necessarily involving a charge of first degree murder, or a sentence of death.5 In this case the jury [369]*369found that the defendant possessed an intent to kill his victim which justified a charge of first degree murder. We acknowledge the trial court’s superior ability to observe witnesses and their demeanor during the sentencing phase of a trial, and especially the unique ability of the trial judge to observe the character and demean- or of the defendant, a tool essential to the ultimate goal of tailoring a sentence to a particular defendant. With that unique ability of the trial court in mind, we have determined that the sentence of death imposed in the present case is not out of proportion to the sentences heretofore imposed. The judgment of conviction and sentence imposed are affirmed.
DONALDSON, C.J., and SHEPARD, J., concur.