Police said Sgt. James Lamprecht was on duty in an unmarked vehicle around 11 p.m. when he saw a car speeding westbound on Fairview Avenue and then blowing the stop sign at Grand Boulevard as it turned south.
The sergeant tried to catch up, but when he crested the hill before a bridge he could not see the car any longer. A few minutes later, a Good Samaritan called 911 to report a car had gone over the bridge and was on fire.
Sgt. Lamprecht was flagged down by the Good Samaritan just north of the bridge on Grand Boulevard, where he saw a dark SUV down the southwest embankment. The SUV had flames coming out of the front where the engine was.
As the officer fetched his fire extinguisher, the Good Samaritan told him someone was trapped in the car; when they got down the embankment, they could see the driver, a man, slumped over the steering wheel and unresponsive.
Lamprecht cut the seatbelt and pulled the driver out and, with the help of the Good Samaritan, began dragging him up the embankment. Other officers arrived to help them.
The driver was taken to St. Mary's Hospital and then flown to a Chicago area by helicopter. He remains unresponsive and in critical condition.
Sgt. Lamprecht injured his knee during the rescue and the department said he will not be working as he recovers.
"His quick thinking and heroism displayed in saving the driver is no surprise to anyone that knows him or works with him," the department said in the statement.
They identified the Good Samaritan as Kevin Gaskin and said, "Without the help from Kevin Gaskin, this could have had a vastly different outcome for the driver and Sgt. Lamprecht."