DOUGLAS COUNTY, Colo. — A 31-year-old man who pleaded guilty to killing two people, including his sister, in Franktown in 2022 was sentenced to almost a century in prison on Monday.

Douglas County Judge Patricia D. Herron sentenced Casey Michael Devol to 97 years in prison for the killing of his sister Jessica Mitchell, 32, her boyfriend Bryan Gray, 34, and a dog in February 2022, according to the Douglas County Sheriff’s Office. They had been shot to death.

The case began on Feb. 8, 2022, when deputies with the sheriff’s office received a call about two deceased people at a home along the 2100 block of S. Russellville Road. The person reported he had walked into the garage to bring a car title to one of his employees and found the bodies.

Mitchell had a gunshot wound to the stomach and Gray had a gunshot wound to the head, according to an arrest affidavit. During Mitchell’s autopsy, authorities found he had in his possession a digital recording device that captured a long audio recording of the events leading up to and including the murders, the sheriff’s office said. Chief Deputy District Attorney Andrew Steers later said this was instrumental in connecting Devol to the crime scene.

Investigators at the initial scene said they believed somebody may have tampered with the evidence since they could not find any firearm or shell casings, according to the affidavit. The home also appeared to have been ransacked. The investigators found security footage on the property that showed a man with long, bushy hair and a beard enter the garage with multiple handguns and a long gun, the document read. A dark-colored truck was also captured in the video.

The day after the shooting, a friend called a detective to say she suspected Devol may have been responsible, though she did not have actual knowledge of his involvement. She told investigators that Mitchell and her brother “did not have a good relationship” and Devol hadn’t been to work at the Town of Castle Rock Water Department in two days, according to the affidavit.

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Investigators confirmed the suspect was Devol and he was arrested on Feb. 9, 2022 after detectives tracked him to a hotel in Salina, Kansas, which is more than 230 miles from the Colorado-Kansas border. He was extradited back to Douglas County, where he was held without bond.

On Sept. 23, 2022, he pleaded not guilty to the charges against him and a jury trial was set to run from Aug. 7 through Aug. 24, 2023. However, on July 19, he entered a guilty plea for two counts of second-degree murder and animal abuse.

He was sentenced to 97 years behind bars on Monday.

“When no eyewitnesses to these murders existed, a digital recorder device became a voice for the victims,” said District Attorney John Kellner. “Jessica likely sensed something was wrong, and her instincts to start a recording and archive the tragic turn of events helped detectives and my prosecutors piece this mystery together and bring justice to their families.”