United States v. Casillas-Montero

Court of Appeals for the First Circuit·Decided September 16, 2025·No. 23-1859·Published

Opinion

United States Court of Appeals For the First Circuit

No. 23-1859 UNITED STATES,

Appellee,

v.

ANTONIO CASILLAS-MONTERO, a/k/a Stone City Kennel, Defendant, Appellant.

APPEAL FROM THE UNITED STATES DISTRICT COURT FOR THE DISTRICT OF PUERTO RICO

[Hon. Silvia L. Carreño-Coll, U.S. District Judge]

Before

Gelpí, Lipez, and Rikelman, Circuit Judges.

Linda A. Backiel for appellant.

Thekla Hansen-Young, with whom W. Stephen Muldrow, United States Attorney, Jonathan L. Gottfried, Assistant United States Attorney, Todd Kim, Assistant Attorney General, Rachel Heron, Ethan C. Eddy, and Allen M. Brabender, Environment and Natural Resources Division, U.S. Department of Justice, were on brief, for appellee.

September 16, 2025

GELPÍ, Circuit Judge. Defendant-Appellant Antonio Casillas Montero ("Casillas") -- a "legend" in the dogfighting world -- pleaded guilty to three counts under the Animal Welfare Act ("AWA"): one count for conspiracy to violate the Animal Welfare Act and two counts for possession of dogs for use in an animal fighting venture. The Presentence Investigation Report ("PSR") calculated the Sentencing Guidelines Range ("GSR") as 12 to 18 months, but it noted that Casillas's conduct could justify both an upward departure under the relevant guideline and an upwardly variant sentence. Citing a medley of factors, the district court imposed on Casillas an 84-month term of imprisonment: 36 months on the conspiracy count, and 24 months on each of the possession counts, all to be served consecutively.

On appeal, Casillas levels a broadside attack on his sentence. He starts with the adequacy of the sentence's explanation, claiming that the district court's stated reasons were inadequate, improper, or both. He then argues that the district court's imposition of consecutive sentences violated the Double Jeopardy Clause of the Fifth Amendment to the Constitution. Finally, he insists that the sentence was substantively unreasonable because similarly situated defendants received lesser sentences. For the reasons explained below, we affirm.

I. BACKGROUND1

The facts of this case, while heinous, are relatively straightforward. For 35 years, Casillas operated Stone City Kennel, where he and at least one co-conspirator bred and trained dogs for dogfighting in the United States and abroad. Known to some as a "legend" in the dogfighting world, Casillas was extensively involved in dogfighting through Stone City Kennel. He trained as many as 40 dogs at a time, employing grueling techniques to enhance the dogs' fighting capabilities;2 sold dogs for thousands of dollars to international clientele; mentored others involved in dogfighting; promoted dogfighting events; and participated in over 150 dogfights across the Americas and the Caribbean, including several U.S. states, Puerto Rico, the Dominican Republic, Mexico, Ecuador, and Peru. None of those facts are disputed.

On October 6, 2022 -- days after Casillas had admitted incriminating information to an undercover federal agent -- a grand jury sitting in the District of Puerto Rico indicted him for

"This appeal arises following a guilty plea, so we draw the 1

facts from the undisputed sections of the presentence investigation report ('PSR') and the transcripts of the change-of-plea and sentencing hearings." United States v. Burgos, 133 F.4th 183, 187 n.1 (1st Cir. 2025) (citation modified).

His training techniques included chaining the dogs to 2

treadmills to walk or run for long distances; giving the dogs steroids and hormones; and holding test fights between dogs at his residence in Humacao, Puerto Rico.

conspiracy to violate the AWA in violation of 7 U.S.C. § 2156 and 18 U.S.C. § 49. Casillas was arrested that same day. Following the arrest, the government searched Casillas's property and found, among other things, four dogs living in poor conditions and suffering from a litany of health problems.3 Those findings gave rise to the November 2022 superseding indictment, which restated the conspiracy count and tacked on four more counts for possession of dogs for use in an animal fighting venture in violation of 7 U.S.C. § 2156(b) and 18 U.S.C. § 49. (In other words, the superseding indictment charged Casillas with one possession count for each dog found on his property during the October 2022 search.) In May 2023, Casillas pleaded guilty to the conspiracy count and two possession counts. The plea agreement did not include an agreed-upon guidelines calculation.

In due course, the Probation Office prepared the PSR.

After recounting the offense conduct in detail, the PSR grouped together the three offenses, calculated a total offense level of 13 and a criminal history category of I, and set the GSR at 12 to 18 months.

Toward the end of the PSR, the Probation Office also included reasons why the district court could both upwardly depart

3 The PSR recites in some detail the grim picture of the four dogs on Casillas's property. All we need to say here is that the dogs were found to have various bacterial and fungal infections, parasites, and lesions. They have all fully recovered.

from the relevant guideline and impose an upwardly variant sentence based on the statutory sentencing factors. First, the PSR cited Application Note 2 to section 2E3.1 of the U.S. Sentencing Guidelines,4 remarking that it permits an upward departure where the offense involves "animal fighting on an exceptional scale." Second, the PSR indicated that the district court could exercise its discretion to impose an upwardly variant sentence after considering the sentencing factors set forth in 18 U.S.C. § 3553(a). The PSR then listed Casillas's relevant conduct for the district court to consider in either departing or upwardly varying. In particular, the PSR pointed to Casillas's participation in more than 150 dogfights over the course of 35 years; the international reach of his dogfighting operation; his

4 Application Note 2 provides in full:

The base offense levels provided for animal fighting ventures in subsection (a)(1) and (a)(3) reflect that an animal fighting venture involves one or more violent fights between animals and that a defeated animal often is severely injured in the fight, dies as a result of the fight, or is killed afterward. Nonetheless, there may be cases in which the offense level determined under this guideline substantially understates the seriousness of the offense. In such a case, an upward departure may be warranted. For example, an upward departure may be warranted if (A) the offense involved extraordinary cruelty to an animal beyond the violence inherent in such a venture (such as by killing in a way that prolongs the suffering of the animal); or (B) the offense involved animal fighting on an exceptional scale (such as an offense involving an unusually large number of animals).

U.S.S.G. § 2E3.1, app. n. 2.

promotion of fights; and his practice of letting dogs die -- rather than removing them and tending to their injuries -- if the dogs were losing during the course of a fight.

Both parties then filed their respective sentencing memoranda. For his part, Casillas advocated for a sentence between 18 and 24 months, emphasizing his personal background and Puerto Rico's tradition of animal fighting as mitigating factors but acknowledging that Application Note 2 might warrant an upward departure. The government disagreed with Casillas's calculation. It sought a 120-month sentence, arguing that either an upward departure or a variance was justified by the magnitude of Casillas's conduct and the section 3553(a) considerations.

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