SAN ANTONIO — The son of a 53-year-old San Antonio woman who was murdered on the city's west side in April has entered a plea deal after confessing to the killing.

18-year-old Matthew Dempsey was in court Thursday, where he entered a plea deal for capital murder. Dempsey will serve up to 42 years in prison for the murder of his mother, Mary Helen Dempsey.

Matthew could be eligible for parole after serving half of his sentence.

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In April, Dempsey provided a full confession admitting to robbing and killing his mother, along with Daniel Saucedo, 18. Saucedo was also charged with capital murder.

At the time of their arrest, investigators with the San Antonio Police Department were alerted after a family member showed up to Mary Dempsey's home. She was found dead in her living room.

According to Matthew's statement to authorities, he and Saucedo were at Mary Dempsey's home gathering items they planned to take when Mary returned to the home. 

After Mary entered the home and turned on the lights, Matthew told police he attacked her with a baseball bat from behind. According to Matthew, Saucedo also joined in and started attacking her with a baseball bat. 

Following the beating, a knife was retrieved from the kitchen and used to cut Mary Dempsey's throat. 

Matthew told police he got a roll of duct tape and gave it to Saucedo to so that the victim could be bound. A blanket was then thrown over the victim. According to the affidavit, Mary's credit cards were given to Saucedo and the items the pair were planning to steal were loaded into her car. The credit cards were used to withdraw money from an ATM.