Two news helicopters fall after colliding in midair while covering a police pursuit in central Phoenix, the United States, Friday, July 27, 2007, killing everyone on both aircraft, police said. Both helicopters were from local television stations. [Xinhua]

PHOENIX, US - Two news helicopters covering a police chase on live television collided and crashed to the ground Friday, killing all four people on board in a plunge that viewers saw as a jumble of spinning, broken images.

Both helicopters went down in a park in central Phoenix and caught fire. No one on the ground was hurt.

TV viewers did not actually witness the accident because cameras aboard both aircraft were pointed at the ground. But they saw video from one of the helicopters break up and begin to spin before the station abruptly switched to the studio.

Television station KNXV reported that it operated one of the choppers. The other was from KTVK. A pilot and photographer aboard each chopper were killed.

KNXV reporter Craig Smith, who was among the dead, was reporting live as police chased a man driving a construction truck who had fled a traffic stop. The man was driving erratically, hitting several cars and driving on the sidewalk at times.

Police had blown the truck's tires, and the man eventually parked it, then carjacked another vehicle nearby.

Just before the picture broke up, Smith said, "Oh geez!"

The station then switched to the studio and briefly showed regular programming, a soap opera, before announcing that the helicopter had crashed.

The man fleeing from police was later taken into custody by a SWAT team after barricading himself inside a house, police said. Police Chief Jack Harris suggested he could be charged in connection with the collision.

"I believe you will want to talk to investigators, but I think he will be held responsible for any of the deaths from this tragedy," Harris told reporters at the scene. He did not elaborate.

National Transportation Safety Board investigators were on the scene Friday and more were on their way from out of state, Phoenix police spokesman Sgt. Joel Tranter said.

The two choppers came down on the grass lawn in front of a boarded-up church at the park. Firefighters swarmed to the area as thick black smoke rose from the scene.

Rick Gotchie, an air conditioning contractor, was working nearby when he noticed the helicopters overhead. He said they began circling closer as he continued watching, and one appeared to get too close to the other.

"I kept saying 'Go lower, go lower,' but he didn't," Gotchie said. "It was like a vacuum. They just got sucked into each other, and they both exploded and pieces were flying everywhere."

He said he ran to the crash site, but "no one got out."

Federal Aviation Administration spokesman Ian Gregor said the pilots of the five news helicopters and one police chopper over the chase were not talking to air traffic controllers at the time, which is normal.

"Typically air traffic controllers clear helicopters into an area where they can cover a chase like this," Gregor said. "Once they are in the area, the pilots themselves are responsible for keeping themselves separated from other aircraft."

Pilots generally use a dedicated radio frequency to talk to each other and maintain their positions, Gregor said.

"There is a high degree of coordination," Gregor said. "To fly for a TV station you have to have a commercial rating, which means more (flight hours), more training."

Gregor said the FAA has not had major safety problems with news chopper operations. "This hasn't been a problem; there hasn't been a trend or a series of issues involving TV helicopters," he said.