An Illinois State Police trooper was killed early Saturday when a wrong-way driver struck his squad car, the third death of a state trooper this year and second in three days.

The driver of the other vehicle also was killed, acting Illinois State Police director Brendan Kelly said. The driver wasn’t identified.

Trooper Gerald Ellis, 36, was returning home when he was hit head-on at about 3:25 a.m. in Green Oaks on Interstate 94 in northern Illinois, state police said. The vehicle was driving eastbound in the westbound expressway lanes. Ellis died at a hospital at about 4 a.m.

“This loss is bitter salt in an open wound,” Kelly said.

Ellis was an 11-year state police veteran with District 15 in Downers Grove. He was a U.S. military veteran and had a wife and two children.

Trooper Brooke Jones-Story was killed Thursday when a truck struck her in Freeport. A vehicle fatally hit Trooper Christopher Lambert in January near Northbrook.

The fatalities come amid a sharp increase in drivers hitting squad cars that are stopped with emergency lights on.