Investigators say one of the cars involved in the accident at 102nd Street and South Indianapolis Avenue was an unmarked police car.
A witness says it looked like the police car was making a traffic stop when another car crashed into it.
" It sounded real loud. It sounded like a major crash, like a car pileup," said the unidentified witness.
According to police, three people went to the hospital in critical condition. Five others also were transported to hospitals, and one other person refused treatment on scene.