(AP) — Four people from Mississippi have died in an early morning accident on Interstate 12 in Louisiana.

Louisiana State Police tell Baton Rouge-area news outlets that the accident happened around 5 a.m. Thursday in Livingston Parish.

Authorities said a Mississippi driver and three passengers were heading east when a westbound car driven by 57-year-old Willie Smith of Loranger crossed the median. What caused the car to cross the median wasn’t immediately known.

State police said none of the people in the eastbound car wore restraints and all four were fatally injured in the resulting crash. Smith was wearing a seat belt. He was taken to a hospital with serious injuries.

I-12 was closed for about two hours after the accident, which remains under investigation.