PORTERSVILLE — A 19-year-old man was found Tuesday night lying on the southbound lane of Route 19 with a head injury, authorities said.

Potential witnesses and bystanders about 8:45 p.m. met rescuers at the possible crime scene. Some hinted at what happened.

“They said (the man) was pushed out or thrown out of a vehicle,” said Brooke Seifert, assistant chief for the Portersville-Muddy Creek Township Volunteer Fire Department.

State police criminal investigators are trying to solve the puzzle. But they’re not saying much.

“We don’t have all the details,” Cpl. Robert Donaldson said this morning. “We’re still looking into it.”

Patrol officers, who answered the initial call, later ceded the case to the department’s crime unit.

Asked if the man, believed to be from the Portersville area, was the victim of an assault, Donaldson admitted he wasn’t certain.

“It’s still early in the investigation,“ he said.

The first call to the Butler County 911 center reported that a “male had been thrown out of a vehicle” on Route 19 near Route 488 in Portersville, said Steve Bicehouse, director of Butler County emergency services.

A Harmony EMS crew joined Portersville firefighters and paramedics at the scene just a couple hundred yards north of Route 488, where they came upon the victim, from the Portersville area.

He earlier had tried to get up but the bystanders had advised him not to move, due to his injuries.

“He had a closed head injury and a contusion on the back of his head,” Seifert said. Rescuers characterized the injuries as “moderate.”

The man was conscious but disoriented. Emergency responders asked him how he ended up in his predicament.

“He seemed to have some memory loss,” Seifert said, “and he really didn’t say what happened. He wasn’t sure.”

Donaldson would not say if police have spoken to the man.

An ambulance drove him to the nearby Portersville fire station. A Life Flight medical helicopter landed there and flew him to Allegheny General Hospital in Pittsburgh.

His condition was unknown this morning.