Sheriff's deputies are still trying to figure out why a man ran over two women, including his mother, on Friday night then tried to kill himself.
On Monday, York County's coroner released preliminary autopsy results on 34-year-old Joshua Grose.
It said that Grose died of blunt-force trauma to his head. Exactly how that happened is still under investigation.
Sheriff's deputies said Grose stole an SUV Friday night from a neighbor, Sandra Thomas, then ran her over and killed her. Then he drove to his house on Mount Gallant Road, ran over his mother, Sandra Grose, killing her, and injuring Curtis Sisk, who lived with them both.
Sandra Grose died in her own front yard.
Joshua Grose was arrested shortly after the killings when deputies found him at home. He walked out of his house naked, looking like he'd just taken a shower.
Early Sunday, deputies said Grose tried to drown himself in a jail cell toilet. Detention officers tried to control him, but he became extremely combative, and started beating his head against the wall. Grose was placed in a restraint chair, but continued beating his head on the wall.
Deputies said he went into cardiac arrest, and later died at the hospital.
Channel 9 asked coroner Sabrina Gast if that head trauma was caused by Grose hitting his head on the wall. She said she didn't want to jump to any conclusions yet. Toxicology tests are pending on Grose, and will take at least two weeks to come in.
Neighbors said they often saw Joshua Grose walking dogs in the neighborhood, and some saw him out walking on the day of the murders.
"It's got to be devastating, got to be devastating," said Lew Cannon, who lives across from the Thomas family. "She was just a nice, nice, nice lady."
Cannon said even though the Grose family lives behind him, he didn't even know their last name until news of the killings broke on Friday night.
Now he wants to urge his neighbors to take care of each other during this tragedy.
"It might entice some people to pack their bags and leave, you know. But I encourage everybody that's here to stick together like we always have," he said.
Late Monday, York County sheriff's investigators still had no information about the motive for the killings.