Jennifer Mitchell (Source: Facebook)

UPDATED: 2/12/2013 11:05 a.m.

CHICAGO (CBS) – A 27-year-old woman was killed in an unusual accident on the Bishop Ford Freeway overnight.

WBBM Newsradio’s Bernie Tafoya reports Illinois State Police said Jennifer Mitchell was either pushed or jumped out of an SUV as it headed south on the Bishop Ford near Sibley Boulevard shortly before 1 a.m.

“We don’t know how she was ejected – if she jumped, if she was pushed – we don’t know that,” said State Police Master Sgt. Jason LoCoco.

This SUV crashed after exiting the Bishop Ford Freeway near 127th Street, after a woman had somehow fallen out of the vehicle. The woman was hit by a semi and a car after she fell out. (Credit: CBS)

After she struck the pavement, Mitchell was struck by a semi and another car. She was pronounced dead at the scene.

However the driver of the SUV kept going. After a chase, the Blazer crashed into another car on the exit ramp from the Tri-State Tollway to 127th Street.

Adam Butler was in that other car and described to CBS 2′s Susanna Song what happened next.

“I saw a white truck come out of nowhere and smash into the side of us, spin me around 3 times. I saw the suspect jump out of car, saw him get out of SUV, and start running.”

Butler did not know what had occurred earlier on the Bishop Ford. He got out of his car and ran after the driver until police caught up.

“When someone hits your car, you chase him,” Butler said. “I had no idea he had been in another accident prior … I thought he was running from police. It’s terrible, really terrible.”

An aspiring nurse, Mitchell studied at Chicago State University. Her friend says Mitchell owned the SUV.

The 28-year-old driver of the SUV was taken to Advocate Christ Medical Center in Oak Lawn for minor injuries. After he was treated, he was taken into police custody for questioning about the incident.

He has not been identified and has not yet been charged.

State police were investigating whether Mitchell had been the victim of another crime involving the driver before she fell from the SUV.