The adopted son of a slain West Ashley woman now faces a murder charge in connection with the death, the Charleston Police Department said this afternoon.

Walker Pinkleton, 21, faces charges of murder and use of a firearm in commission of a violent crime, police Cpl. Fred Bowie said.

Pinkleton is the adopted son and biological grandson of 59-year-old Patricia Walker, who was found shot to death Sunday in their home at 958 Orange Grove Road.

He had been charged with grand larceny after the police said he was spotted driving Walker’s vehicle when he wasn’t allowed to.

Walker’s husband was out of state at the time, and since Friday, Pinkleton had told friends and family members that his adoptive mother couldn’t come to the phone or go outside.

Deputy County Coroner Scott Ramsey said this afternoon that an autopsy pinpointed Walker’s time of death between Friday night and Saturday morning.

Family members from Columbia called the police when they grew concerned after failing to reach Walker.

Pinkleton, who was said in court documents to have drug problems, was on probation for a burglary charge. He also has two past arrests on drug possession counts.

Reach Andrew Knapp at 937-5414 or twitter.com/offlede.