WASHINGTON TOWNSHIP, N.J. — Investigators were looking for evidence Wednesday of what caused a news helicopter to crash in the New Jersey Pinelands the night before, killing the pilot and photographer on board.

Chopper 6 from WPVI-TV in Philadelphia was returning from an assignment at the Jersey Shore when it went down Tuesday night in a section of Wharton State Forest in Washington Township, Burlington County, authorities said.

The TV station said the crash occurred around 8 p.m. The New Jersey State Park Police said they were notified of a helicopter that had gone missing shortly before 11 p.m.

“A pilot and a photographer from our news team were in the helicopter when it went down while returning from an assignment at the Jersey Shore” on Tuesday night, WPVI-TV in Philadelphia reported. “Both crew members were killed.”

The station did not release their names pending notification of family members.

“Our hearts are just broken for these men. They're broken for their families,” reporter Katherine Scott said Wednesday morning, reporting from near the scene of the crash. “We just can't believe this has happened.”

The area is part of the New Jersey Pinelands, a million-acre wilderness area that stretches across more than seven counties and features dense woods, rivers and rare plant species.

Video taken from a WTXF-TV helicopter over the wreckage site showed scattered debris, with some pieces on fire or smoking, as authorities searched with flashlights in the darkness.

The cause of the crash was not immediately clear. The National Transportation Safety Board arrived at the crash site at 3:15 a.m. Wednesday and took control of the investigation.

An officer with the park police found the wreckage shortly after midnight, said George Fedorczyk, chief of the department.

“Due to the remote location of the scene and the limited visibility, it was determined at that point that the investigation would be suspended until sometime after daybreak,” he said at a morning news conference Wednesday. “Know that our thoughts are with the pilots, their families and the media community.”

WPVI-TV reported that it leases the helicopter from U.S. Helicopters Inc., which is based in North Carolina. A spokesperson said company officials were not prepared to comment Wednesday morning.

Emails seeking comment were sent Wednesday to New Jersey State Police, the New Jersey State Park Police and the FAA.

There have been other deadly helicopter crashes involving staff from television stations in the United States. Among them was a July 2007 crash, when two helicopters from KNXV-TV and KTVK-TV collided over Phoenix while covering a police chase. Four people — both pilots and two photographers — were killed.