State Police investigators suspect alcohol may have been a factor in a crash that left an off-duty Slidell police officer hospitalized with life-threatening injuries and killed his passenger early Sunday morning in St. Tammany Parish.

The officer was identified as 31-year-old John Cole, of Slidell. His front-seat passenger was identified as 31-year-old Daniel Hanlon, also of Slidell.

Cole was headed west on La. 433 in a 2005 Jeep Wrangler about 4:30 a.m. when he failed to maneuver a left curve in the roadway and ran off the road to the right, according to State Police. He overcorrected to the left and lost control of the Jeep, sending it into a ditch, where it overturned.

Cole was not wearing a seat belt and was rushed to Interim LSU Hospital in New Orleans, State Police said.

He was in critical condition Sunday evening, said Detective Daniel Seuzeneau, a Slidell Police Department spokesman.

Hanlon died at the scene.

State Police said “impairment is suspected on Cole’s part” and a blood sample was taken from him for a toxicological analysis.

“This situation has devastated the entire Slidell Police Department as many officers were close with both John Cole and Daniel Hanlon,” Seuzeneau said in a prepared statement. “All we can ask for at this time are prayers for the friends and families of those involved with this tragic accident.”

Toxicology tests are pending. Cole faces possible charges in the crash, State Police said.