The victims included Siemens executive Agustin Escobar, his wife, Merce Camprubi Montal, and three children, in addition to the pilot, a person briefed on the investigation told The Associated Press. The person could not discuss details of the investigation publicly and spoke on condition of anonymity.
Photos posted on the helicopter company's website showed the couple and their children smiling as they boarded just before the flight took off.
The flight departed a downtown heliport around 3pm on Thursday (5am Friday AEST) and lasted less than 18 minutes. Radar data showed it flew north along the Manhattan skyline and then back south toward the Statue of Liberty.
Video of the crash showed parts of the aircraft tumbling through the air into the water near the shoreline of Jersey City, New Jersey.
Witness Bruce Wall said he saw the helicopter "falling apart" in midair, with the tail and rotor coming off. The rotor was still spinning without the helicopter as it fell, he said.
Dani Horbiak was at her Jersey City home when she heard what sounded like "several gunshots in a row, almost, in the air". She looked out her window and saw the chopper "splash in several pieces into the river".
The helicopter was spinning uncontrollably with "a bunch of smoke coming out" before it slammed into the water, said Lesly Camacho, a hostess at a restaurant along the river in Hoboken, New Jersey.
The weather was overcast at the time of the crash, but visibility over the river was not substantially impaired. Rescue crews had to deal with seven-degree water temperatures.
Rescue boats circled the submerged aircraft within minutes of impact near the end of a long maintenance pier for a ventilation tower serving the Holland Tunnel. Recovery crews hoisted the mangled helicopter out of the water just after 8pm using a floating crane.
Divers helped remove the victims from the water. Four were pronounced dead at the scene, while two were taken to area hospitals where they died.
The flight was operated by New York Helicopters, officials said.
New York Helicopter Tours owner Michael Roth said the pilot had radioed base to say the helicopter was returning to the helipad - but it never arrived.

"I got a call from my manager and my downtown heliport and she said she heard there was a crash, and then my phone blew up from everybody.
"Then one of my pilots flew over the Hudson and saw the helicopter upside down."
Roth said everyone at the company was devastated.
"My wife has not stopped crying," he said. "The death of the child of any human being is a monumental disaster."

The National Transportation Safety Board said it would investigate.
Escobar worked for tech company Siemens for more than 27 years, most recently as global chief executive for rail infrastructure at Siemens Mobility, according to his LinkedIn account. In late 2022, he briefly became president and chief executive of Siemens Spain. In a post about the position, he thanked his family, "my endless source of energy and happiness, for their unconditional support, love ... and patience".
Escobar regularly posted about the importance of sustainability in the rail industry and often travelled internationally for work, including journeying from India to the United Kingdom in the past month. He was also vice president of the German Chamber of Commerce for Spain.
His wife, Camprubi Montal, worked in Barcelona, Spain, for Siemens Energy for about seven years as its global commercialisation manager, according to her LinkedIn account.
Video of the crash suggested that a "catastrophic mechanical failure" left the pilot with no chance to save the helicopter, said Justin Green, an aviation lawyer who was a helicopter pilot in the Marine Corps.
It was possible the helicopter's main rotors struck the tail boom, breaking it apart and causing the cabin to free-fall, Green said.
"No pilot could have prevented that accident once they lost the lifts," Green said. "It's like a rock falling to the ground. It's heartbreaking."
The skies over Manhattan are routinely filled with planes and helicopters - private recreational aircraft as well as commercial and tourist flights. Manhattan has several helipads that whisk business executives and others to destinations throughout the metropolitan area.
At least 38 people have died in helicopter accidents in New York City since 1977. A collision between a plane and a tourist helicopter over the Hudson in 2009 killed nine people, and five died in 2018 when a charter helicopter offering "open door" flights went down into the East River.
Thursday's crash was the first for a helicopter in the city since one hit the roof of a skyscraper in 2019, killing the pilot.
New York Helicopters also owned a Bell 206 that lost power and made an emergency landing on the Hudson during a sightseeing tour in June 2013. The pilot managed to land safely, and he and the passengers - a family of four Swedes - were uninjured. The NTSB found that a maintenance flub and an engine lubrication anomaly led to the power cut-off.
In January, an American Airlines jet and an Army helicopter collided in midair in Washington - the deadliest US air disaster in a generation.
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