Federal investigators say they'll examine everything from flotation devices to passengers' bags to determine why a tour helicopter crashed and sank in New York City's East River.
National Transportation Safety Board member Bella Dinh-Zarr said today it will be some time before that finding is made.
Yesterday's crash killed all five passengers aboard, except for the pilot, Richard Vance, who survived.
Dinh-Zarr said the helicopter's floats inflated, but investigators will look at whether they deployed properly.
A federal official told The Associated Press the pilot told authorities he believed a passenger's bag might have been responsible for the crash after hitting an emergency fuel shutoff switch.
The official was briefed on the investigation but was not authorised to speak publicly about it and spoke on condition of anonymity.