NORTH UTICA, Ill. (AP) — Authorities say three people have died after a black powder device exploded along a bank of the Illinois River in the northern part of the state.

First responders were called to an area west of the Starved Rock State Park boat ramp where they discovered three dead males around 7:20 p.m. Thursday.

LaSalle County Coroner Rich Ploch says the three died from injuries they received in the explosion. Autopsies are planned. The victims’ names haven’t been released. The explosion occurred about 75 miles (120 kilometers) southwest of Chicago.