A spokesman for Mayor Eric Phillips confirmed the deaths. Three others were taken to the hospital where they later died.
Ms Dinh-Barr said "air traffic control, operations, air worthiness, survival factors, power plants and weather" would be investigated by the NTSB as to what caused the crash.
Andrew Vidales, McDaniel's cycling coach at Bishop Lynch, said McDaniel "always had a smile on his face, very talkative and very optimistic".
The helicopter is commonly used by tour companies and is owned by New Jersey-based Fly Liberty Charter. Owner Liberty Helicopters is referring all inquiries to investigators. The company could not be reached for comment. "Screaming help and waving his arms like this", said Brianna Jesme and Celia Skvaril who witnessed the crash.
Nigro said the pilot was at a hospital and in "OK" condition.
The red helicopter was hired for a photo shoot, according to The Associated Press.
After it crashed, it flipped over nearly immediately, its landing skids pointing into the air, she said.
Residents of Roosevelt Island and those dining on the water had front row seats to the incident but were captured by paralysis and an inability to save the aircraft as it landed in the middle of the 50-foot-deep river. But it looked nearly like it was supposed to land, like it was making an emergency water landing. What we're going to look at is how they inflated, if there were any problems with them. "Then the next minute, it was diving into the river".
The skies over NY constantly buzz with helicopters carrying tourists, businesspeople, traffic reporters, medical teams and others. Flightradar.com, a flight-tracking website, shows the aircraft passing by the Statue of Liberty and the Brooklyn Bridge before the flight ended in the middle of the East River just after 7 p.m.
"There's no way those people could have gotten out of the helicopter", Adams told the Post.
Paramedics and members of the FDNY perform CPR on a victim of a helicopter that crashed into the East River. The crash drew crowds of people to the waterfront.
Blanco was a tourist from Corrientes, Argentina, who'd been in New York for a few days, said her country's consul in New York, Mateo Estreme.
"East River - engine failure", he added. "It was sinking really fast". "Then it went more steady and it crashed into the river".