HOBOKEN, New Jersey (AP):

Divers recovered a piece of a submerged helicopter and a fourth body yesterday as investigators searched the Hudson River for wreckage from the helicopter and a small plane that collided in mid-air, killing nine people.

Investigators also were searching for pictures and video of Saturday's accident, which was seen by thousands out enjoying a beautiful summer day.

Nine people - three members of a Pennsylvania family in the private plane, five Italian tourists and a pilot from New Jersey in the Liberty Tours helicopter - died in Saturday's collision. It was the city's worst air disaster since a 2001 commercial jet crash in Queens that killed 265 people.

One of the Italian victims was a husband celebrating his 25th wedding anniversary, a family friend said. His wife had stayed behind, but their 16-year-old son was also in the helicopter.

The fourth body was recovered by midmorning yesterday, two law enforcement officials told The Associated Press. The officials spoke on condition of anonymity because all the bodies have not yet been recovered or identified.

National Transportation Safety Board Chairman Debbie Hersman said a nearby helicopter pilot saw the plane approaching the in-flight helicopter and tried to alert his fellow pilot. He radioed the doomed helicopter and said, "You have a fixed-wing behind you," but there was no response from the pilot, Hersman said.

The pilot then saw the plane's right wing clip the helicopter, and both aircraft split apart and fell into the river, she said.

The two aircraft went down just south of the stretch of river where a US Airways jet landed safely seven months ago. But this accident was, in Mayor Michael Bloomberg's words, "unsurvivable".