Hours after a family member found a woman slain Tuesday in an apparent robbery at the victim's West Side home, police arrested her son as the main suspect in the death.

Officers initially responded around noon to a reported robbery in the 7600 block of Stagecoach Lane. A relative had gone to check on the woman, identified as Mary Dempsey, 53, and noticed her car was missing and her home looked like it had been broken into.


The relative went inside and made the gruesome discovery. When investigators arrived it became clear the case had transformed into a homicide investigation, said Doug Greene, a spokesman for the San Antonio Police Department.

"We can't confirm that she died by gunshot or cutting, but what we can tell right now is there's obvious trauma to the body," he said at the time.

The car is still missing but police say they plan to charge Dempsey's son, Matthew Dempsey, 18, with capital murder. Matthew Dempsey, who did not live with his mother, was questioned by investigators Tuesday before Greene announced his arrest.

READ ALSO: Two killed in shooting at South Side apartments

"It's a heartbreaking story," Greene said. "To find out that it was the son of the victim involved in this, it's just kind of hard to process but the evidence shows otherwise and we have to go by the evidence."

Police are still looking for the victim's car, a beige Honda Accord with the license plate JWC2803. Anyone who sees the car or has information on the woman's death is asked to call the department's homicide unit at 210-207-7635.

Earlier in the day, Johnny Arredondo, a neighbor who is currently running for City Council in District 4, said his wife and son heard gunshots Monday night but added the noise wasn't uncommon for the neighborhood.

"If we don't hear (police) helicopters at night, it's unusual," he said.

Drugs and robberies are a common problem in the area, Arredondo noted, as he pointed to almost every surrounding home noting they had been broken into or vandalized.

READ ALSO: 4 injured in knife fight that began as a parking dispute, police say

"It's always been a problem up and down this street," he said.

As he spoke, another neighbor stood in her driveway, stifling tears upon hearing the news of the Dempsey's death.

Text "NEWS" to 77453 for breaking news alerts from mySA.com

cdowns@mysa.com | @calebjdowns