ALTADENA, Calif. (AP) — Federal officials are investigating a collision involving two police helicopters in the Los Angeles area that left five officers and a civilian with minor injuries.

Investigators believe Saturday's crash occurred when the rotator blades touched of a chopper that was landing and one that was taking off, Lt. Phlunte Riddle said.

The collision caused extensive damage to both aircraft, crumpling the tail and breaking the blades of one and causing the blade to fall off and other damages to the other.

The injured were taken to hospitals for evaluation after the 4 p.m. collision at a helipad in Altadena. Riddle said they included a pilot and an observer in each of the Bell OH-58A helicopters and two officers on the ground. One of the observers was a civilian.

One helicopter crew was on routine patrol and the other was assigned to monitor traffic from the UCLA-Southern California football game at the Rose Bowl, she said.

The weather was drizzly and cloudy at the time of the accident.

The FAA and the National Transportation Safety Board were investigating.

The collision follows a much more serious crash in Atlanta this month where two officers in a police helicopter were killed when the aircraft hit wires atop a power pole.