Richard Vance said passenger’s bag may have struck the emergency fuel shutoff button, causing accident that killed five people.

The pilot of the helicopter that crashed in New York City’s East river, killing five people, has reportedly said a passenger’s bag could have caused the accident.

Richard Vance told investigators a bag may have struck the emergency fuel shutoff button on the Eurocopter AS350, a law enforcement official told CNN.

The Liberty Helicopters aircraft landed in the water at about 7pm. Vance was the sole survivor. In a radio transmission released after the crash, the pilot can be heard saying “Mayday, mayday, mayday” and “East river engine failure”.

Video taken by a bystander showed the red helicopter descending slowly into the water, before listing on to its right-hand side. Vance was able to free himself and was rescued by a tugboat.

ABC News reported that the helicopter entered the water around East 86th Street, near Manhattan’s Upper East Side. It then floated “a mile or two south”, officials told ABC, before emergency crews could bring it to a halt.

Fire department of New York commissioner Daniel Nigro told reporters the helicopter turned upside down in the water, complicating recovery efforts. “One of the most difficult parts of the rescue were that five people were tightly harnessed,” Nigro said. “People had to be cut out.”

The National Transport Safety Board was leading the investigation into the crash. On Monday morning, the agency said it was sending “14 NTSB personnel” to the site.

An employee of Liberty Helicopters, which offers private charters and sightseeing tours, said the company was “not flying today”. The helicopter had been privately chartered for a photoshoot, officials said. The crash drew crowds of people to the waterfront.

“It’s cold water,” witness Mary Lee told the New York Post. “It was sinking really fast. By the time we got out here, we couldn’t see it. It was underwater.”

Another bystander, Susan Larkin, told the Associated Press she went down to see rescue boats in the river and a police helicopter circling overhead, hovering low over the water. “You could clearly see they were searching,” she said.

Others reported seeing someone in the water clinging to a flotation device.

It is the third crash involving Liberty Helicopters in the past 11 years. In 2009, nine people were killed when a helicopter collided with a plane over the East river. Five Italian tourists and the pilot were onboard the helicopter and three people, one of them a child, were travelling in the plane.

Two years earlier, one of Liberty’s helicopters fell 150m during another sightseeing trip. The pilot was able to land the aircraft safely in the Hudson river and help evacuate the seven passengers.