Defendant in 1989, 1990 murder and sexual assault cases in Mesa is sentenced to life imprisonment

Mar 15, 2024, 11:00 AM

Thomas David Cox, the defendant in two decades-old  homicide and sexual assault cases, was sentence...

Thomas David Cox, the defendant in two decades-old homicide and sexual assault cases, was sentenced to life in prison on March 12, 2024. (Mesa Police Department and AP File photos)

(Mesa Police Department and AP File photos)

PHOENIX — The defendant in two decades-old cold cases involving murder and sexual assault in Mesa was sentenced to life in prison on Monday, authorities said.

Thomas David Cox, 61, received life imprisonment with the possibility of release after 25 years for the homicide and 10 years for the sexual assault, both to run concurrently, the Maricopa County Attorney’s Office said.

His sentencing follows his guilty plea in February of one count of first-degree premeditated murder and one count of aggravated assault.

“One of the most agonizing aspects of cold cases is the long uncertainty endured by victims and their families,” County Attorney Rachel Mitchell said in a press release.

“This defendant committed these offenses in such a cruel manner and then went on to have a full life while the victim’s young life was halted. It’s only appropriate that this defendant spend the rest of his life in prison.”

Mesa cold case: Everything we know about the murder and sexual assault

Cox murdered 22-year-old Susan Amy Morse in October 1989 and sexually assaulted a women in November 1990.

Morse was found dead in her apartment near Southern Avenue and Country Club Drive.  An investigation revealed she suffered blunt force trauma to multiple parts of her body and was strangled with an electrical cord, authorities said.

The second crime occurred in the same apartment complex when Cox broke into a 23-year-old woman’s home and sexually assaulted her before stealing cash and a VCR from the residence, authorities said. The victim, whose identity wasn’t released, survived.

DNA samples collected at each of the crime scenes were found to match each other in November 2002, but authorities couldn’t identify a suspect at that time.

Here’s how Mesa detectives got a break in the cold case

The Mesa Police Department announced the arrest of Cox in April 2022 after a follow up was conducted on the cold cases. A family line was developed using DNA technologies that identified Cox as the suspect.

A fingerprint comparison between a previous misdemeanor case Cox was arrested for and those retrieved from the crime scenes was conducted and resulted in a match.

A DNA test was conducted after Cox was arrested and it matched both crime scene profiles, authorities said.

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Defendant in 1989, 1990 murder and sexual assault cases in Mesa is sentenced to life imprisonment