Matthew Dempsey, 18, and Daniel Saucedo, 18, have each been charged with capital murder for the alleged killing, which was initially thought to be a random robbery.
Cops arrested Dempsey on Tuesday after interrogating him and apparently learned more information on Wednesday about Saucedo’s alleged involvement that led to him being hit with charges.
Investigators believe the teens were, in fact, robbing Mary Dempsey — Matthew’s 53-year-old mother — when she returned home and walked in on them sometime Monday night or early Tuesday.
According to the arrest affidavit, which was obtained by the San Antonio Express-News, Dempsey and Saucedo entered the West Side residence using a key. They allegedly “ransacked” the place, the affidavit says.
When Mary arrived home, her son allegedly attacked her from behind with a bat and Saucedo eventually joined in with his own, the affidavit says. The teens then got a knife from the kitchen and slit her throat, according to the documents.
Mary’s daughter would later find her dead — in a pool of her own blood — with a blanket covering her, the affidavit says.
“A canvass was conducted and information was obtained that two males were seen leaving the victim’s home,” wrote police officials.
Bloody clothes were allegedly found inside Dempsey’s mobile home and the teen’s girlfriend informed police that he told her about killing his mother, according to the affidavit. Cops say Dempsey later confessed to the murder. He and Saucedo were being held on $1 million bail Wednesday.