Atlanta police on Monday were seeking a black 2005 Chevrolet Impala that struck and critically injured a man who was crossing a street on the city's northwest side over the weekend.

Nathan Powell, 25, was struck by a hit-and-run driver about 11:30 p.m. Friday, police said. The victim initially was treated by Atlanta Fire Rescue and was transported by Grady ambulance to Grady Memorial Hospital, where he remained in critical condition Monday.

Police said Powell's last known address was Chattanooga, but a family member told Channel 2 Action News that the man now lives in Montgomery. The relative said Powell is on life support at Grady.

The man had just gotten off an eastbound MARTA bus on the 1300 block of Joseph E. Boone Boulevard, and was crossing the street behind the bus when he was hit, Atlanta police said.

The Chevy, traveling west on Boone, pushed the victim about 40 feet and then fled the accident, police said. Witnesses told investigators that the Impala may have been racing a red vehicle at the time.

Police said the Chevy has dark-tinted windows and possible front body damage or damage to the windshield. Anyone with information about the accident was asked to call Atlanta police hit-and-run traffic fatality unit at 404-765-2808.