OPINION
DOUGLAS, Judge.
Murriel Don Crawford appeals from his conviction upon a plea of guilty to the offense of capital murder. Punishment was assessed at death.
The record reflects that a few minutes after midnight on the morning of October 22, 1975, appellant was awakened in his apartment by co-defendant David Mabra. Approximately forty-five minutes later, Mabra and appellant drove to the farm of Jack Watson, a former employer of Ma-bra’s. There they stole a hunting knife, lariat rope and binoculars from an International Scout parked on the farm property, along with two .12 and .410 gauge shotguns and a .22 caliber rifle. They then went to appellant’s apartment with the stolen goods.
A short time later, appellant and Mabra drove in appellant’s pickup truck to a 7 — 11 Store, intending to rob the cashier. They abandoned their plan and proceeded to an Exxon service station with similar intentions. They again became nervous and left the station without robbing the attendant. Finally, appellant and Mabra drove to a Toot ’n Totum food store and parked appellant’s truck where it could not be readily seen. Carrying the .410 shotgun which had been stolen from Jack Watson, the pair entered the store and robbed the night cashier, Edith Whitfield, of $32.00. After Mrs. Whitfield handed appellant the contents of the cash register in a paper bag, appellant fired at her, narrowly missing her head. Appellant then fired a second shot at point blank range and struck Mrs. Whitfield in the left eye, causing her instantaneous death.
The two men fled the scene of the murder and returned to appellant’s apartment. There they gathered together all the goods which had been stolen from the Watson farm and placed them, along with the murder weapon, in the trunk of Mabra’s car. The pair got into the car and headed for Jack Watson’s farm but were stopped en route by Amarillo police officer Tom Porter because the muffler made excessive noise. A traffic citation was issued to Mabra and both defendants were interviewed by Officer Porter. Mabra gave the officer permission to search the car, but the officer declined and appellant and Mabra were told they were free to go. They proceeded to the Watson farm where they replaced the stolen items, including the murder weapon, in the Scout from which they had been taken. Appellant and Mabra drove back to Amarillo.
[928]*928Three weeks after the murder of Edith Whitfield, appellant and Mabra initiated a conversation with Jim White, a neighbor and friend. In the course of this conversation, appellant bragged to White that he and Mabra had robbed the Toot ’n Totum store‘and that he himself had shot the deceased in the eye and “pushed her brains out the top of her head.” Appellant described for White their flight to the Watson farm, their encounter with the Amarillo police and other details of the crime. He related that they returned to the scene of the crime intending to see whether or not the Toot ’n Totum was equipped with cameras which might have recorded the murder and robbery on film. Appellant stated to White that if Officer Porter had opened the trunk of Mabra’s car he would have stabbed him. Jim White testified that as appellant described the grisly details of the crime he showed no shame, sorrow or guilt. Appellant’s only regret was, as he told White, that he did not stop to eat candy while in the Toot ’n Totum store.
Jim White informed Amarillo police detective Gary Richards of his conversation with appellant and Mabra. Both appellant and Mabra were interviewed by Detective Richards concerning the crime and were released. Following their release, they returned to the Watson farm and stole the .410 and .12 gauge shotguns which they had previously stolen. The guns were sold by appellant to two workers at Maywood, Inc., where he was employed.
Prior to his arrest, appellant admitted to three fellow employees at Maywood that he had murdered the deceased. Karen Richie testified that appellant told her that he had done the shooting. He laughed about the incident. Sandra Carreker testified that appellant stated to her on a coffee break, “Maybe they’ll come and get [me] for shooting that old lady.” On that occasion, too, he laughed about the murder. Keith Car-reker testified that appellant told him that he “shot that old bitch in the face.” Car-reker stated that when he asked appellant if he was drunk, appellant answered that he was cold sober and that if Carreker said anything to anyone about the murder his partner would “waste him.”
Ricky Wayne Holik testified that in January, 1976, he, David Mabra and the appellant attended a concert in Amarillo. After the concert, at appellant’s instigation, the three of them went to Maywood, Inc. There they burglarized the building and stole a number of tools. To destroy evidence of the breakin, appellant set fire to the building. On August 25, 1976, appellant and Mabra were arrested for the burglary of the Maywood plant. While in custody, appellant confessed to the burglary and, later, to the murder of Edith Whitfield. His written confession was admitted into evidence at trial.
Thirteen grounds of error are advanced in appellant’s brief. First he complains of testimony wherein reference was made to an oral statement of the co-defendant David Mabra.
“Q. (Prosecutor) And did you thereafter have a discussion and an interview with Don Crawford?
“A. (Detective Richards) I did.
“Q. Also with a fellow named David Mabra?
“A. Yes.
“Q. In any event, after your — did you have occasion to ask the defendant, Don Crawford, inquire whether or not he or Richard or David Mabra had been involved as the robbers and murderers in that Toot ’n To-tum murder?
“A. Yes, I did.
“Q. Did they admit it, deny it, or what?
“A. They denied it.”
Appellant contends that since David Mabra was not on trial and did not testify any statement made by him was inadmissible against the appellant.
There was no objection to the testimony. Mabra’s statement, although hearsay as to the appellant, was not inculpatory. Under such circumstances, any error committed was harmless. Thomas v. State, 533 S.W.2d 796 (Tex.Cr.App.1976).
[929]*929Appellant contends that the trial court erred in permitting the district attorney to read sections of David Mabra’s inadmissible initial confession while cross-examining the appellant. He contends that the prosecutor did not cross-examine appellant from the statement, but that he used cross-examination as a guise under which to introduce large portions of the co-defendant’s confession before the jury. He also complains of the following statement made by the district attorney during his cross-examination of appellant:
“You are still sticking to the version you gave after Mabra fingered you, that Mabra took [the gun] in.”
Appellant argues that the prosecutor’s remarks made reference to the confession of the non-testifying co-defendant in which appellant was blamed for the actual shooting.
In light of the fact the jury returned a directed verdict upon appellant’s plea of guilty, it cannot be said that the improperly admitted confession contributed to appellant’s conviction. A plea of guilty before a jury admits all of the elements of the offense and is conclusive of a defendant’s guilt. See Fierro v. State, 437 S.W.2d 833 (Tex.Cr.App.1969).
Appellant, however, contends that the evidence bore heavily on the jury’s determination of the special issues which, under Article 37.071(d)(2), (e), V.A.C.C.P., resulted in the assessment of the death penalty. In his written confession which was introduced into evidence by defense counsel he admitted that he was a party to the robbery and murder of Edith Whitfield. He also testified that he helped prepare for and commit the robbery. He denied, however, carrying the gun or shooting the deceased. The prosecution, in cross-examining the appellant, read certain portions of David Mabra’s first confession which named appellant as the one who carried the weapon into the store and shot the deceased. It is appellant’s theory that the jury assessed the death penalty on the basis of its belief that appellant was the “trigger man”, and that without David Mabra’s confession it would have assessed a life sentence.
Appellant testified that he signed the confession in order to clear his conscience and that he felt a great sense of relief after having done so. It was only after reading Mabra’s statement that appellant said to Detective Garrett: “My God, he’s putting us both in the electric chair,” whereupon he immediately gave a written statement admitting his involvement in the crime but placing the blame for the shooting on David Mabra.
Article 38.24, V.A.C.C.P., provides:
“When part of an act, declaration or conversation or writing is given in evidence by one party, the whole on the same subject may be inquired into by the other, as when a letter is read, all letters on the same subject between the same parties may be given. When a detailed act, declaration, conversation or writing is given in evidence, any other act, declaration or writing which is necessary to make it fully understood or to explain the same may also be given in evidence.”
In Vanderbilt v. State, 563 S.W.2d 590 (Tex.Cr.App.1978), we observed that Article 38.24 does not restrict the explanatory act, declaration, conversation, or writing to the time when the act, declaration, conversation or writing sought to be explained occurred but extends the rule so as to render such acts or statements admissible, if necessary to a full understanding of, or to explain the acts or statements introduced in evidence by the adverse party.
Mabra’s confession was read aloud to appellant by Detective Garrett during the conversation preceding appellant’s confession. Appellant having introduced his own statement into evidence, the State was properly permitted to give evidence of other writings, conversations and transactions which fully explained appellant’s confession, the context in which it was given and the motive behind it. In short, the prosecution was entitled to prove the whole of what was said immediately prior to appellant’s confession under Article 38.24, supra.
Even if it had been error for the prosecutor to read portions of the co-defendant’s confession while cross-examining [930]*930appellant, such error would not merit reversal. The other evidence against appellant was, as a whole, overwhelming. The evidence which, in particular, showed appellant to have been the trigger man was so great as to render the co-defendant’s statement relatively insignificant. Appellant admitted to four friends that he had shot Edith Whitfield. As in Schneble v. Florida, 405 U.S. 427, 92 S.Ct. 1056, 31 L.Ed.2d 340 (1972), the appellant’s confession was minutely detailed and completely consistent with the objective evidence. And, as in Schneble, “the ‘minds of an average jury’ would not have found the State’s case significantly less persuasive” had the prosecutor’s recitation of Mabra’s confession been excluded. There was a joint trial in the Schneble case. In the present case there was no joint trial. We conclude that the reasoning in the Schneble case applies here. If any error was committed, it was harmless.
Next, appellant asserts that the prosecutor was erroneously permitted to inject false evidence at trial. During cross-examination, the following exchange took place between the district attorney and appellant:
“Q. You had something to shoot Mrs. Whitfield with, though, didn’t you ?
“A. Not in my possession.
“Q. Walked in there with a loaded gun, didn’t you ?
“A. No, sir.
“Q. You are still sticking to the version you gave after Mabra fingered you, that Mabra took it in ?” (Appellant’s emphasis)
Appellant contends that by these remarks the prosecutor implied to the jury that appellant was lying when he denied carrying the .410 shotgun into the Toot ’n Totum.
Appellant argues that the prosecutor’s remarks concerning his carrying of the murder weapon were made in bad faith and with knowledge of their falsity. The basis for this contention is the fact that in his second confession David Mabra denied shooting Edith Whitfield but admitted that he initially carried the gun into the store. In his brief, appellant claims that a polygraph examination of Mabra supported the truth of his second written statement. Appellant theorizes that the prosecutor knew the results of the polygraph, knew that appellant did not carry the gun into the Toot ’n Totum, and consequently, should not have implied to the jury that appellant walked into the Toot ’n Totum brandishing the murder weapon. For the prosecutor to do so, appellant asserts, was to introduce before the jury evidence which he knew to be false.
This contention is without merit. Appellant assumes that the district attorney was obligated to believe David Mabra’s second statement (in which he admitted carrying the gun into the store) and disbelieve Mabra’s initial confession (in which he stated that appellant carried the gun). The prosecutor was under no such obligation regardless of the fact that a polygraph examination had been conducted. Results of polygraph examinations, by virtue of their unproven reliability, have consistently been held to be inadmissible for any purpose. Reed v. State, 522 S.W.2d 466 (Tex.Cr.App. 1975); King v. State, 511 S.W.2d 32 (Tex.Cr.App.1974); Lewis v. State, 500 S.W.2d 167 (Tex.Cr.App.1973); White v. State, 496 S.W.2d 642 (Tex.Cr.App.1973). The prose cutor had no duty whatever to rely on such inadmissible and potentially unreliable data in determining which of David Mabra’s confessions were true. The prosecutor had no duty to believe either of Mabra’s statements. Appellant, having voluntarily taken the stand, was subject to being discredited like any other witness. In his attempt to impeach appellant’s testimony, the prosecutor was free to reject the co-defendant’s versions of the crime and vigorously cross-examine the appellant concerning his possession of the murder weapon immediately prior to the shooting. Myre v. State, 545 S.W.2d 820 (Tex.Cr.App.1977); Weber v. State, 472 S.W.2d 136 (Tex.Cr.App.1971); Patterson v. State, 338 S.W.2d 469 (Tex.Cr. App.1960).
Appellant contends that the court erroneously allowed into evidence extraneous offenses of burglary and arson. Ricky Wayne Holik testified at length concerning [931]*931appellant’s commission of burglary and arson at Maywood, Inc. There was no objection to such testimony until after Holik had completed his testimony on direct examination. Thereafter, appellant took the stand and, on direct examination by defense counsel, testified to having committed the burglary of Maywood, Inc. The admission of improper evidence will not constitute reversible error where the defendant voluntarily gives testimony the same as that which is admitted over objection. Cowan v. State, 562 S.W.2d 236 (Tex.Cr.App.1978); Lovell v. State, 538 S.W.2d 630 (Tex.Cr.App.1976); Allen v. State, 536 S.W.2d 364 (Tex.Cr.App.1976); Watson v. State, 532 S.W.2d 619 (Tex.Cr.App.1976); Dogget v. State, 530 S.W.2d 552 (Tex.Cr.App.1975).
Even if error had not been waived, evidence of appellant’s extraneous offenses would nevertheless have been admissible. Inasmuch as such offenses showed appellant’s tendencies toward criminal conduct, they were relevant and admissible pursuant to Article 37.071, V.A.C.C.P., which gives the trial court wide discretion in determining what evidence may be offered. Robinson v. State, 548 S.W.2d 63 (Tex.Cr.App.1977); Livingston v. State, 542 S.W.2d 655 (Tex.Cr.App.1976). No error is presented.
Appellant next argues that the prosecution erred in failing to provide the defense with a copy of an exculpatory police report prior to trial. The requested report stated that appellant had been cleared after his initial interrogation concerning the murder of Edith Whitfield. Appellant alleges that the report was relevant on numerous issues but particularly so on the issue of the vol-untariness of his confession and that it should, therefore, have been produced at a pretrial Jackson v. Denno1 hearing.
He relies upon Ridyolph v. State, 503 S.W.2d 276 (Tex.Cr.App.1974), and cases cited therein for the proposition that it is reversible error for the prosecution to either actively suppress or inadvertently fail to disclose evidence which might exonerate or be of material value to the accused.
In determining whether reversible error has occurred, this Court must look to the three factors which the Supreme Court deemed relevant in Moore v. Illinois, 408 U.S. 786, 92 S.Ct. 2562, 33 L.Ed.2d 706 (1971). Those factors are (1) the suppression of such evidence by the prosecution after a request by the defense, (2) the evidence’s favorable character for the defense, and (3) the materiality of the evidence. Considering these factors as applied to the facts of the present case, we conclude that no reversible error is shown.
The record before us does not reflect that the requested police report was suppressed by the prosecution. Prior to trial, appellant filed a motion for the disclosure of exculpatory evidence. At the pretrial hearing appellant’s motion was granted. Immediately thereafter, and before the State had had an opportunity to comply with the appellant’s motion, a pretrial hearing was conducted on the voluntariness of appellant’s confession. During the hearing appellant demanded immediate production of the requested report. In view of the fact that the State did furnish appellant with a copy of the report during trial, it cannot be said that such evidence was deliberately or even inadvertently withheld.
Neither can it be said that the requested report was material. In United States v. Agurs, 427 U.S. 97, 96 S.Ct. 2392, 49 L.Ed.2d 342 (1976), the Supreme Court held that (1) 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, and (2) that the omitted evidence must have been such as would create a reasonable doubt about the defendant’s guilt. The police report in the present case, had it been provided prior to trial, would not have created a reasonable doubt as to the voluntariness of appellant’s confession. Regarding the report’s relevance to other issues raised at trial, appellant is not in a position to complain inasmuch as the report, including the exculpatory portions, was admitted into evidence and a copy thereof was furnished to counsel.
[932]*932When appellant pled guilty, it was immaterial that the officer might not have concluded that he had enough evidence upon which to charge appellant.
Next appellant complains of the prosecution’s failure to disclose negative fingerprint test results until the day of trial. He does not allege that any harm resulted from this delay in disclosure. Nor has it been shown that the test results were exculpatory in nature, thus obligating the State to disclose them to appellant. Had they been exculpatory, any error in their delayed disclosure to appellant must be considered harmless in light of appellant’s guilty plea and the overwhelming weight of the evidence.
Appellant next alleges that the court erred in excusing potential juror Martha B. Stulce for cause on the grounds that neither the requirements of Witherspoon v. Illinois,2 nor V.T.C.A., Penal Code, Section 12.31, were satisfied. No objection was raised. Failure to object to the improper exclusion of a potential juror waives such error on appeal. Boulware v. State, 542 S.W.2d 677 (Tex.Cr.App.1976); Granviel v. State, 552 S.W.2d 107 (Tex.Cr.App.1977).
In four grounds of error appellant alleges that the court erred in refusing to grant a mistrial after the prosecutor introduced before the jury evidence of an oral statement made by the appellant in which he denied committing the charged offense. The statement was neither inculpatory nor prejudicial. Appellant’s objection was sustained and an instruction to disregard was given. Error, if any, was cured. Sternlight v. State, 540 S.W.2d 704 (Tex.Cr.App.1976); Smith v. State, 540 S.W.2d 693 (Tex.Cr.App.1976); Marlow v. State, 537 S.W.2d 8 (Tex.Cr.App.1976); Paredes v. State, 500 S.W.2d 160 (Tex.Cr.App.1973).
He also complains of the following testimony by Karen Richie:
“Q. (By the Prosecutor) Did you talk to David — yes, to David Mabra — about the shooting of Mrs. Whitfield?
“A. No sir. When he took his lie detector test—
“MR. FAIRWEATHER: Your Honor, I move for a mistrial at this time.”
The witness’ answer, although unresponsive, neither prejudiced appellant nor reflected upon his guilt or innocence. The witness’ statement made no reference to appellant, but rather, concerned the co-defendant David Mabra. Error, if any, was harmless.
Appellant urges that the prosecutor erred in refusing to furnish appellant a copy of the State’s witnesses’ statements until after such witnesses had testified. Appellant’s contention is without merit and contrary to this Court’s holding in White v. State, 496 S.W.2d 642, 645 (Tex.Cr.App.1973); and Hoffman v. State, 514 S.W.2d 248, 253 (Tex.Cr.App.1974).
Next he contends that the court erroneously admitted the appellant’s written confession into evidence on the grounds that it was induced by police officers’ promises that the death penalty would not be sought. The evidence adduced at the Jackson v. Denno hearing showed appellant’s confession to have been freely and voluntarily given. Appellant was duly warned of his rights and subjected to no coercion or abuse of any kind. We do not find, nor does appellant direct our attention toward any evidence that appellant’s confession was induced by promises that the death penalty would not be sought. Moreover, the confession was introduced by appellant himself. Any complaints regarding its vol-untariness were thereby waived. Morales v. State, 466 S.W.2d 293 (Tex.Cr.App.1971).
Finally, appellant attacks the sufficiency of the evidence upon which the jury could have returned an affirmative finding on special issue No. 2, i. e., that a probability existed that the appellant would commit criminal acts of violence which would constitute a continuing threat to society. Article 37.071(d)(2), V.A.C.C.P. Appellant urges that reversal is required because no testimony was offered by the State specifically in support of this special issue.
[933]*933It is well established that the introduction of expert psychiatric or psychological testimony is not a prerequisite for a jury finding of “yes” on special issue No. 2. Brock v. State, 556 S.W.2d 309 (Tex.Cr.App.1977); Burns v. State, 556 S.W.2d 270 (Tex.Cr.App.1977); Granviel v. State, 552 S.W.2d 107 (Tex.Cr.App.1977). The testimony adduced at trial concerning the crime itself and the circumstances surrounding its commission may be more probative on special issue No. 2 than any other evidence which the State might offer. Brock v. State, supra; Burns v. State, supra.
In the present case, as in Brock, the evidence showed that appellant committed a brutal and senseless murder in the course of a robbery even though the deceased had surrendered the contents of the cash register to him and offered no resistance. Appellant’s intent was not merely to terrorize the deceased with the initial shotgun blast. His intent was to cause her death by firing again at point blank range. He was later heard to laugh and to brag about the fact that he had seen Edith Whitfield’s brains pushed out the top of her head. His statements to Keith Carreker and Jim White reflected his willingness to kill again. After admitting his responsibility for the murder to Keith Carreker, appellant threatened to have him killed if Carreker revealed what he knew to anyone else. Appellant also told Jim White that he would have stabbed Officer Tom Porter if he had attempted to search the trunk of David Ma-bra’s car.
Three months after the murder of Edith Whitfield, appellant committed the offenses of burglary and arson. In committing the latter offense, appellant knowingly created a risk that loss of human life could occur. Both offenses were probative on the issue of whether appellant was likely to commit criminal acts of violence subsequent to the offense charged in the indictment. See Granviel v. State, supra, and Felder v. State, 564 S.W.2d 776 (1978).
For any of his actions appellant showed no remorse or sorrow whatever. His only regret, as has been noted, appeared to be that he did not seize the opportunity to eat candy in the Toot ’n Totum store following the murder. We find that sufficient evidence was presented from which the jury could conclude that a probability existed that appellant would commit future acts of criminal violence which would pose a continuing threat to society.
No reversible error having been shown, the judgment is affirmed.
CLINTON, J., not participating.