CHICAGO (CBS) — An Illinois State Trooper was released from the hospital Tuesday morning, several hours after he was injured in an altercation with an armed motorist on the Tri-State Tollway.

Police said the altercation happened around 7 p.m. Monday at the Halsted Street toll plaza in the northbound lanes of Interstate 294 in South Holland.

The trooper saw a “suspicious person” at the toll plaza, and when he confronted the person, a struggle ensued, and the suspect’s gun discharged several times, state police said.

The trooper, who was injured in the neck, but not by gunfire, was transported to a hospital. He was released Tuesday morning and was doing well, police said.

The suspect — described as an African American male wearing a “construction type” vest and black jeans — fled on foot and was still at large Tuesday morning, police said.

A weapon was recovered at the scene.

A person of interest in the case was taken in for questioning on Monday, but has been cleared, according to police.

Anyone with information is asked to call the Illinois State Police at 630-241-6800- Extension 5028.