The Eisenhower Expressway reopened Thursday evening after investigators cleared the scene near Mannheim Road.
HILLSIDE, Ill. — Federal investigators said a man found dead Thursday on the Eisenhower Expressway was killed by an explosion in a vehicle near Mannheim Road, after a response that closed Interstate 290 for much of the day.
The finding shifted the case from a broad death investigation to a federal probe centered on the blast. The FBI and ATF said the incident appeared limited to the vehicle and the person who died. Officials have not released the man’s name or a final cause and manner of death.
Authorities responded about 10 a.m. Thursday to I-290 near Mannheim Road, where a vehicle sat on the roadway and investigators kept traffic away from the scene. The closure affected lanes in both directions and backed up drivers across the west suburbs. The vehicle was later removed as evidence crews worked along the expressway.
ATF officials said the investigation involved federal, state and local agencies, along with emergency responders. The agency said investigators determined the incident was an explosion that killed one individual. Officials also said they found no evidence that the blast was connected to another event or that anyone else took part.
The Cook County medical examiner’s office said an autopsy completed Friday did not settle the cause or manner of death. Further studies were pending. The office had described the person killed only as a white male, and officials had not said when his identity would be released.
The expressway closure lasted until about 7 p.m. Thursday, when all lanes reopened. Drivers had been sent away from the area during the investigation, and no other injuries were reported. Federal officials have not said what kind of explosive material may have been involved.
As of Saturday, investigators had not announced arrests, suspects or a public safety threat. The case remains open while federal agents and the medical examiner’s office continue their reviews.
Author note: Last updated June 6, 2026.