A helicopter belonging to NBC’s Los Angeles affiliate crashed and burst into flames Tuesday evening in the Chatsworth neighborhood, northwest of downtown Los Angeles, while it was being used to cover a fatal road collision.

At least three people were reported killed and a fourth injured, according to the supplied report. A spokesperson for the Los Angeles Fire Department said at least one victim was found in the parking lot beside a storage building. Officials were still determining whether the other two victims had been on the aircraft or on the ground.

“We’re trying to determine how many patients were inside the helicopter,” fire department spokesperson Branden Silverman said. The department said crews were searching the wreckage after sending dozens of firefighters to the scene and quickly extinguishing the flames.

NBC’s local affiliate identified the aircraft as NewsChopper4. It had been traveling to cover a collision between an SUV and a city bus that killed two people. Reporters at the bus crash said the helicopter came down about a mile away.

NBC reported that it had been unable to contact the crew, but there was no immediate confirmation of the identities of anyone aboard. Aerial footage showed parts of the helicopter, including the tail and rotor, among storage containers and vehicles.

The US National Transportation Safety Board and the Federal Aviation Administration have opened investigations into the cause of the crash. The cause was not immediately clear, according to the supplied material.