ST. LOUIS — A man who died following a shootout with police on a busy stretch of interstate near St. Louis was heavily armed, wearing a bulletproof vest, and had threatened to kill a relative and co-workers, investigators said Monday.

The incident began around 9 a.m. when several passing motorists stopped to help 31-year-old Jerrod Kershaw after he ran his vehicle off the road near the intersection of Interstate 55 and Interstate 270 outside St. Louis, said Jefferson County Sheriff Dave Marshak.

Kershaw — wearing a bullet-proof vest and brandishing a gun — tried to carjack one vehicle but couldn’t because it had a manual transmission, Marshak said. He then stole another Good Samaritan’s car and drove south on I-55.

Within moments, police received two alarming phone calls.

The first was from Kershaw’s mother, who said her son was driving to nearby De Soto, Missouri, to kill a relative and then himself, Marshak said.

Almost immediately, someone called told police in Pacific, the St. Louis suburb where Kershaw lived, to report that Kershaw had made “homicidal and suicidal” threats against his workplace. Marshak declined to identify where Kershaw worked.

Police then spotted the stolen car, and a chase began along I-55 in St. Louis County. Police used stop strips that forced the car off the roadway in neighboring Jefferson County.

Kershaw fired several shots at police, who returned fire, Marshak said.

Police closed the interstate in both directions, and a SWAT team and armored police vehicle descended on the stolen car. Kershaw was found dead inside the vehicle, which television footage showed was riddled with bullet holes. Police haven’t said how he died.

Marshak said Kershaw had several weapons in the car.

“Had we not been able to engage this individual, who knows what might have happened,” St. Louis County Police Chief Jon Belmar said.

No officers were hurt during the chase and shootout, and there were no reports of injuries to bystanders. Belmar said police were still investigating to make sure Kershaw didn’t commit other crimes earlier in the day.

No publicly listed phone numbers could be found by The Associated Press for Kershaw’s residence or possible relatives in the area.

Traffic backed up for miles in both directions along I-55 during the incident. Northbound lanes reopened Monday afternoon, but southbound traffic was re-routed onto other roadways.


Sign up for The Associated Press’ weekly newsletter showcasing our best reporting from the Midwest and Texas: http://apne.ws/2u1RMfv