The wreckage of a helicopter is lifted by crane from the Hudson River and placed on a boat on Sunday. (Seth Wenig/Associated Press)Divers found the wreckage of a plane that collided with a sightseeing helicopter over the Hudson River on the weekend, killing nine people, a New Jersey state police official said Monday.

The single-engine Piper was found in 15 metres of water less than a quarter of a kilometre from the New Jersey side of the river, Lt. Albert Ponenti said.

Divers had returned to the water as of 2:45 p.m. ET on Monday after suspending the search earlier in the day because of poor conditions, New York police spokesman Paul Browne said.

Police also said they located the body of one of the two people on the plane on Monday but couldn't immediately dislodge it from the underwater wreckage. They didn't say if it was the plane's pilot or the adult passenger.

Members of a Pennsylvania family and an Italian tour group died Saturday when the small plane and the helicopter collided over Manhattan.

Divers had already recovered seven bodies from the Hudson River — one teenage passenger from the plane, and all five passengers and the pilot from the helicopter.

The river's strong current and deep, murky waters, which reduced visibility to 30 centimetres, forced divers to suspend the search Monday morning.

Two law enforcement officials identified the plane's pilot as Steven Altman, 60, of Ambler, Pa. Also in the plane were the pilot's brother, Daniel Altman, 49, of Dresher, Pa., and Daniel's 16-year-old son, Douglas.

The five tourists on the helicopter were from the Bologna, Italy, area.

Italian media identified them as Fabio Gallazzi, 49, his wife Tiziana Pedrone, and their son, Giacomo Gallazzi, 16, together with Michele Norelli, 52, and his son, Filippo Norelli, 17.

The helicopter pilot has been identified as Jeremy Clark of Lanoka Harbor, N.J.

The pilots of both aircraft are believed to have been experienced and to have logged many hours in their aircraft. They are also not currently believed to have had any outstanding health issues that may have contributed to the incident, officials said.

Helicopter wreckage retrieved

The wreckage of the helicopter was retrieved with a crane by the U.S. Army Corps of Engineers on Sunday from nine metres of water near the New Jersey shore.

Debbie Hersman, chief of the National Transportation Safety Board, fields questions from reporters about a mid-air collision of a sightseeing helicopter and a small plane that killed nine people. (Max Pasion/Associated Press)Officials said a sonar scanner found the Piper Lance and more plane parts nearby under about 15 metres of water.

"We think we've had some positive hits on the skin of the airplane and we're very hopeful they'll be able to pull that up today," said Debbie Hersman, chief of the National Transportation Safety Board.

The investigation into the crash is expected to take months, she said.

The plane took off from Teterboro Airport a little before noon Saturday. Hersman said it was not required to have a flight plan and did not file one. The plane was flying at about 330 metres at the time of the crash, she said. Below that altitude, planes in that part of the Hudson River corridor are to navigate visually. Above that, they need clearance from air traffic controllers.

Witnesses said the small plane approached the Liberty Helicopter Tours aircraft, which had just taken off for a 12-minute tour, and appeared to clip it with a wing.

Hersman said she will not be speculating on the cause of the crash, but said the helicopter was gaining altitude at the time the two hit.

The collision has raised questions about how the airspace above the Hudson River is governed and Hersman said the NTSB will look at those policies during its investigation.

Scattered debris

Both aircraft split apart and fell into the river, scattering debris.

Investigators will also eventually examine the aircrafts' structural integrity, she said.

The NTSB has long expressed concern that federal safety oversight of helicopter tours isn't rigorous enough. The agency said 120 mid-air collisions have occurred in the United States since 1999, including Saturday's crash. Of those, 64 were fatal, killing 171 people.

Liberty Tours' helicopters have recorded eight accidents since 1995, according to the NTSB. Saturday's collision was the company's first fatal accident.

The collision is the worst air disaster in New York City since a commercial jet crash in Queens killed 265 people in November 2001.

With files from The Associated Press