The gunshot deaths of a young couple in western Clarion County are being investigated as an apparent murder-suicide, state police said.

Authorities identified the couple as Jeremiah P. Heller, 22, and Lexis Walker, 19. Police believe the couple died early Sunday evening.

Family members discovered the bodies at the apartment the couple shared on Main Street in St. Petersburg, investigators said, adding that both died of gunshot wounds.

A black pistol was found near them, and two spent casings were discovered between them, according to authorities.

Police said they believe they know who the shooter was, but declined to elaborate, citing the ongoing investigation.

Investigators said they have evidence for their theory of a murder-suicide, but would not confirm if they found a written note or document at the scene to suggest a reason for the shootings.

No autopsies were planned, police said

Clarion County Coroner Dan Shingledecker pronounced Heller and Walker dead. He declined further comment.

District Judge Jeffrey Miller signed a search warrant about 3:20 p.m. Sunday for the apartment and a vehicle that belonged to Heller. That vehicle was found in a parking lot adjacent to the apartment building.

Walker, formerly of Allegheny Township in northern Butler County, was a senior at Allegheny-Clarion Valley High School.

District Superintendent David McDeavitt, in the wake of Walker's death, issued a message to the school community and staff.

“On Sunday, the school district was informed that a member of the senior class at Allegheny-Clarion Valley High School passed away over the weekend,” he said in the statement. “The apparent cause of death was homicide.”

He said police indicated to him that there was no threat to public safety.

“This is truly devastating news for the entire A-C Valley School District Community,” the statement said, “While we do not have further details to share at this time, we are working with local law enforcement officials to assist in their investigation in any way we can.”

McDeavitt noted Monday that grief counselors are available this week to speak with students by telephone or web conferencing. Anyone needing assistance is asked to call 724-659-4661, or visit the district's website at acvsd.org to set up an appointment.

“We ask our community members to join us in keeping the family and friends of the student in your thoughts at this time,” he said.

Nearly four years ago, Walker was the subject of a state police search after she went missing from her then-home in Allegheny Township for more than 36 hours.

Helicopters, police dogs and numerous volunteers, including firefighters from more than a half-dozen departments, aided in the May 2016 search.

Walker, who was 15 at the time, later showed up on the front porch of her family's home. She was tired and hungry, the family told police, but she did not have any apparent physical injuries.

In an interview with the Butler Eagle following her return, she recounted her ordeal, blaming her initial disappearance on her search for a missing horseshoe.

Later, she said she became afraid after losing a magnetic stick belonging to her stepfather.

“I'm a sensitive person, and I didn't want to get in trouble,” she told the Eagle at the time. “I just got so scared and wanted to run off — (I) thought it might be better that way.”

She apparently got lost in the woods for a time before she eventually regained her bearings and returned home.