Two Mississippi men were killed over the weekend when their semi truck left the roadway and crashed into an Illinois river, becoming submerged.

The incident happened on Saturday, April 14, around 6 a.m. Illinois State Police say that truck driver Michael C. Goffinet, 48, was westbound on I-64 in White County when the crash happened. At approximately mile marker 124, the truck left the interstate for unknown reasons, drove onto the median, and crashed into the Little Wabash River, where it became submerged.

The bodies of Goffinet and his co-driver, 36 year old Charles Boggs were later recovered by authorities and the two men were pronounced dead on the scene.

White County Coroner Chris Marsh says that Boggs was likely in the sleeper berth when the crash happened, according to the Courier & Press. Marsh says Goffinet was able to get out of the truck but couldn’t make it out of the river.

Authorities are still working to determine the cause of the fatal crash.