A gunman who killed four people before attempting to take his own life was driven by an obsession with one of his victims, friends and family say.

The Pittsburgh Tribune-Review reports that Timothy O’Brien Smith, 28, opened fire at a car wash in Fayette County, Pennsylvania, early Sunday morning, killing four people before turning the gun on himself. Smith is being treated for his injuries but according to multiple reports is not expected to survive.

William Scott Porterfield, 27; Seth William Cline, 21; Cortney Sue Snyder, 23; and Chelsie Lou Cline, 25, were all killed in the mass shooting. Smith reportedly had a female passenger in his car who avoided serious injury, suffering only cuts from broken glass, and is now cooperating with police.

Chelsie Lou Cline’s half-sister Sierra Kolarik told the Pittsburgh Tribune-Review that Smith and Chelsea knew each other and had possibly dated briefly, and that he was obsessed with her. She said that while Smith’s primary interests were “guns and guns and guns and shooting and beer and rolling cigarettes,” he came across as a kindhearted person.

“I don’t understand,” she said. “I still don’t believe it.”

Four days before she died, Chelsie posted a joking message on Facebook that Smith appeared to have taken seriously.

“After this week, I (really) need to get taken out… on a date or by a sniper either one is fine (with) me at this point,” Chelsea wrote on Wednesday, according to the Pittsburgh Tribune-Review.

Tim Smith responded.

“I could do both,” he wrote.

At about 3 a.m. Sunday morning, Smith reportedly arrived to Ed’s Car Wash with an AR-15 semi-automatic rifle, a 9 mm handgun, and a .308 rifle in his vehicle. He was also wearing body armor. The victims reportedly arrived in two separate vehicles. Chelsea Cline and Williams Scott Porterfield reportedly drove together, and were shot as they exited their car. Seth William Cline and Cortney Sue Snyder were reportedly shot and killed while inside their vehicle.

Porterfield left behind his pregnant wife, Jenna Porterfield, who told the Pittsburgh Tribune-Review that the couple was working through a rough patch.

“I’m not holding that against Will. We weren’t fighting. We were fixing,” Jenna Porterfield said.

“And if he was with someone else while we were having problems, honestly, I don’t care what he did. I’m not going to hold that against him.”

“I’d give anything to have him back,” she said.

According to the latest reports, Smith remains on life support.

[Feature image: Facebook/Chelsea Cline]