Police, who had originally reported five dead, have not yet released the names of the victims.
It was not immediately clear whether the shooter was among the dead, but authorities told local media outlets there was “no threat to the community, no imminent danger.”
Details were scarce Sunday, as police and other emergency vehicles swarmed the tiny carwash 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 carwash parking lot.
Later Saturday, WPXI News reported the shooting had stemmed from a domestic dispute, according to interviews with family members of the victims.
Shari Bukovac, who owns the carwash with her husband, Ed, told The Washington Post Sunday that, although the automated carwash is open 24 hours a day, no employees were on the property when the shooting took place.
A neighbor called them in the middle of the night to inform 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 carwash in the roughly two decades they’ve owned it.
“I guess at night there’s been some people hanging out there,” she said. “We’ve been broken into a time or two. But otherwise, people are just hanging out down there, I guess.”
This post has been updated.