Wyoming Supreme Court Stands Firm On Murder Conviction

CASPER, Wyo. — The Wyoming Supreme Court has upheld the conviction of James Franklin Mavigliano, who was found guilty of second-degree murder and possession of a controlled substance in connection with the 2024 killing of Chance Arias at a Casper motel.

Mavigliano appealed only his murder conviction, arguing that the district court erred by failing to include a self-defense interrogatory—a special question—on the jury’s verdict form. The court ruled there was no plain error, affirming both his conviction and sentence of 62 years to life in prison.

According to court records, police were called to Topper Bob’s Motel on March 5, 2024, where they found Arias dead in his room with injuries consistent with assault and strangulation. Surveillance footage showed Mavigliano and a woman, later identified as Amber Cook, entering and leaving the room multiple times that evening. Officers arrested Mavigliano nearby with a meth pipe, the room key, and a blue duffle bag containing a broken, bloody lamp believed to have been used in the killing.

During a police interview, Mavigliano admitted to killing Arias after an argument, saying he believed Arias was about to hit him. He struck Arias several times, hit him with a lamp, and eventually strangled him with the lamp cord. He later acknowledged that Arias never physically attacked or threatened him.

At trial in December 2024, Mavigliano’s defense claimed he acted in self-defense, but the jury rejected that argument. On appeal, Mavigliano contended that the verdict form should have required jurors to make a unanimous finding about self-defense.

In its decision, the state’s high court found no Wyoming law requiring such a special interrogatory and noted that the jury had been properly instructed on self-defense and the need for a unanimous verdict. “The district court did not commit plain error,” the justices wrote.

The conviction and sentence were affirmed.