Men Receive Lengthy Prison Sentences for 2023 Murder of Colorado Jeweler
Charles Robinson Shay was sentenced to life in prison plus 120 years while his accomplice, Michael James McCormack, got 75 years.

The Colorado First Judicial District Attorney’s Office announced that on Monday, Michael James McCormack, 51, was sentenced to 75 years in prison after being found guilty of felony murder and aggravated robbery, among other charges.
The other man charged in the case, 42-year-old Charles Robinson Shay, was found guilty in a separate trial of 10 counts in connection with Arguello’s death, including first-degree murder, second-degree kidnapping, and aggravated robbery.
Jurors also found Shay, who has six prior felony convictions, to be a “habitual criminal” under Colorado law, a charge that can lead to longer prison sentences.
Shay was sentenced to life without the possibility of parole plus 120 years on Sept. 10, the DA’s office said.
Arguello, 64, was the owner of Peter Damian Fine Jewelry & Antiques, a store he opened in 2007.
According to the DA’s office, Arguello’s wife, Teresa Casillas, said during sentencing that after her husband’s death, they had to close their business because, “Peter was the reason customers came to the store.”
“He was committed to working at least 10 more years because he loved his little shop and took so much pride in its treasures. Unlike most of us, going to work was fun for him,” she said.
In a post on Facebook, the Wheat Ridge Police Department described the late jeweler as a friend, mentor, and father figure in the Wheat Ridge community.
“His shop was a welcoming, safe place where you were always greeted with a smile,” the post reads.
“Peter embodied the kind of optimism and compassion we try to exemplify in our community and in our police department … Justice will not bring Peter back, but we sincerely hope this outcome will allow Peter’s family to heal. They are part of our family now, forever and always. As we move forward, we honor his memory by living life with joy and kindness.”
Arguello was in his store on the morning of Nov. 29, 2023, when Shay and McCormack came in.
Prosecutors and Arguello’s family argued during trial that McCormack earned Arguello’s trust in order to gain access to the store and then target him, keeping tabs on the jeweler “like a lurking, cunning predator.”
During the robbery, it was Shay who bound Arguello with flex cuffs, assaulted him, and fatally shot him, the DA’s office said.
Both men were seen by witnesses fleeing through the back door and getting into a red Chevy Silverado—which police later determined had been stolen—that was found after it had been set on fire.
DNA found on the flex cuffs linked Shay to the crime, and he was formally charged in January 2024.
Police issued a warrant for McCormack on March 7, 2024, and arrested him on May 2 following a two-month search.
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