CHICAGO (CBS) — Illinois State Police say a 48-year-old tollway maintenance worker was sideswiped by a semi and was killed Monday afternoon – the semi did not stop.

State Police Master Sergeant Jason Bradley said 48-year-old David M. Schwarz was hit on southbound I-294, south of Cicero Avenue and 127th Street, near Alsip around 12:20 p.m.

Bradley said the man was killed.

Sources said Schwarz was working with a partner picking up debris on the shoulder of the road and was hit as he walked to the driver side of the work truck. His partner called for help.

“He was picking up debris along the right shoulder of the roadway,” said Illinois State Police Master Sergeant Jason Bradley. “As he walked back to his vehicle, toward the driver’s side of his vehicle, a semi-truck pulling a trailer sideswiped the worker and his vehicle.”

The worker’s partner saw a semi truck pulling a trailer pass through about the same time his coworker was hit, according to sources.

900600c205ff48b0a0f00ea281d9fff6 Tollway Worker Struck, Killed By Vehicle On I 294

David Schwarz (photo provided to CBS)

Illinois police are looking for that truck and its driver for questioning about the incident, but sources said they are not sure if that truck was actually involved in the accident.

Master Sergeant Bradley said the state police crash reconstruction officers will be investigating and state police will be looking for the vehicle and its driver.

Schwarz, who lived in south suburban Monee, was pronounced dead at 12:43 p.m., the medical examiner’s office said.

Schwarz served as an equipment operator laborer since beginning his career at the tollway in March 1992, according to the tollway’s statement. He was married and a father of two children.

“David worked on the front line of our 292-mile roadway system, performing duties that included removing snow, maintaining safe roadway conditions and, most vitally, assisting drivers who were stranded or needed help,” according to the tollway’s statement. “He was carrying out his duties when he tragically lost his life.”

“We offer our deepest condolences and our full support to David’s family, loved ones and friends for their heartbreaking loss.”

The crash remains under investigation.

If you have any information about this incident, you are asking to call Illinois State Police.

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