4 injured after medical helicopter crashes in Chicago

CHICAGO — Officials say four people were injured, one critically, after a medical helicopter crashed on Chicago's South Side.

The Federal Aviation Administration says the crash occurred around 9:15 p.m. Saturday near the intersection of three expressways.

Chicago Fire Deputy District Chief Walter Schroeder says the patient in the helicopter was taken to a hospital in critical condition, while the three crew members onboard were transported in stable condition.

Schroeder says the pilot issued a "mayday" call before the crash, but the exact cause is not yet known. He also commended the pilot for putting the aircraft down in a grassy area away from traffic.

It's unclear where the flight originated or where it was headed. The FAA says investigators are heading to the scene.