BUCKLEY, Ill. (AP) — Police say a southern Illinois man’s body was found inside a tanker filled with gas after two truck drivers noticed the fuel was not flowing smoothly during unloading.

Iroquois County Coroner Bill Cheatum tells WCIA-TV that the drivers were trying to unload the tanker Friday at a gas transfer hub in Iroquois County when they found the body after opening the tanker to determine why the fuel wasn’t flowing smoothly.

WICS-TV reports that Illinois State Police identified the dead man as 29-year-old Garrett Mayer of Nashville, Illinois. An autopsy was conducted Saturday, and toxicology results are pending. The Iroquois County Sheriff’s Office is investigating Mayer’s death.