Two people killed in fiery crash on Dan Ryan

An off-duty Chicago police officer crashed his sport utility vehicle into a car parked along an expressway early Friday, causing a fiery explosion that killed two people, authorities said.

The officer tried to flee after being helped from his vehicle by a passerby, but was apprehended quickly and taken to a local hospital, State Police Sgt. Juan Valenzuela said.

Chicago police said in a statement that the 41-year-old officer is an 18-year veteran who worked in the detective division. The statement said an internal affairs investigation had begun the officer would be "relieved of his police powers."

The accident happened shortly before 4 a.m. along the Dan Ryan Expressway on the city's South Side, police said. Valenzuela said the car had pulled to the side of the expressway before it was struck from behind.

Killed were driver Andrew Cazares, 23, of Summit, and passenger Fausto Manzera, 21, of Chicago, Valenzuela said.

The Cook County medical examiner's office did not immediately release the cause of death, and a spokesman did not return a phone message.

Valenzuela said the officer driving the SUV, whom he would not identify, was taken to Northwestern Memorial Hospital, where he remained late Friday afternoon. A hospital spokeswoman could not immediately confirm whether the officer was there or his condition.

"The one car with the two occupants in was completely involved in fire," said Bruce Gebien of the Chicago Fire Department. "We were able to put it out fairly quickly. They were trapped in the vehicle. The vehicle was crushed. And so if they weren't killed by the impact, they were killed by the fire."

Witnesses and police say that passersby tried to help the victims out of the stalled car but were unable. They also tried to help the man out of the SUV, and when they did, police say that he fled.

ABC7 Chicago and the Associated Press contributed to this report.