Four people are dead after an overnight shooting at a Pennsylvania car wash, authorities said.

The incident took place about 3 a.m. Sunday at Ed’s Car Wash in Melcroft, about 50 miles southeast of Pittsburgh, police told WPXI News.

Four of the victims were pronounced dead at the scene, while the alleged gunman is reportedly on life support at a hospital. All the victims were in their 20s and 30s, the news station reported.

Police, who originally reported five dead, have not yet released the names of the victims.

Details were scarce Sunday, as police and emergency vehicles swarmed the tiny car wash throughout the morning. By Sunday afternoon, the question of what sparked the shooting was still unanswered.

“There is no indication of drug activity at this point,” Pennsylvania State Police spokesman Robert Broadwater told the Pittsburgh News-Gazette. “But we have no motive, no reason.”

Broadwater also told the newspaper that two of the victims were discovered inside a green pickup truck, while two others were found dead outside in the car wash parking lot.

Later Saturday, WPXI News reported the shooting stemmed from a domestic dispute, according to interviews with family members of the victims.

Shari Bukovac, who owns the car wash with her husband, Ed, told The Washington Post on Sunday that, although the automated car wash is open 24 hours a day, no employees were on the property when the shooting happened.

A neighbor called them in the middle of the night to tell them of the shooting, Bukovac said, adding that they still didn’t know much more than what was being reported on television.

Bukovac characterized Melcroft, an unincorporated community in western Pennsylvania’s Fayette County, as “fairly quiet,” and said nothing of this magnitude has happened at the car wash in the roughly two decades they’ve owned it.