CHICAGO --Chicago police are investigating a possible hit-and-run on the Northwest Side.Several Chicago police squad cars were on the scene at W. North Avenue and N. Campbell in Humboldt Park. Some lanes of traffic were also shut down. A witness says a man was hit by a car that drove off from the scene. The man had just been inside Alex Medina's store seconds before the accident. "The guy came out of the store, went across the street, guy just ran him over and kept going, didn't stop," said Medina, witness. There's no word on the injured man's condition.