Authorities on Monday identified two pilots who died after their helicopters collided midair in southern New Jersey.

Kenneth Kirsch, 65, and Michael Greenberg, 71, were friends who both lived in New Jersey and would often have breakfast together at a cafe near the crash site in Hammonton, about 35 miles (56 kilometers) southeast of Philadelphia.

Hammonton Police Chief Kevin Friel stated that Kirsch, from Carney’s Point, was pronounced dead at an area hospital after being flown there, while Greenberg, of Sewell, died at the crash site.

“Statements from witnesses had the two helicopters flying close together just before the crash,” he said. “The crash site was approximately a mile and a half from the airport in a farm field.”

Investigators from the National Transportation Safety Board collected evidence at the site on Monday, following a report of an aviation crash at about 11:25 a.m. Sunday. Video footage from the scene illustrated one helicopter spiraling rapidly to the ground before flames engulfed it.

The Federal Aviation Administration explained the collision involved an Enstrom F-28A helicopter and an Enstrom 280C helicopter. Only the pilots were on board each aircraft.

Sal Silipino, owner of a cafe near the crash site, shared that the pilots were regulars. He recalled witnessing their takeoff before one suddenly began to spin downward, followed by the second.

Hammonton resident Dan Dameshek reported hearing a loud snap as he exited a gym, leading him to witness the terrifying scene of the helicopters spiraling out of control.

Experts believe investigators will focus on inter-pilot communications and visibility factors to ascertain the cause of the collision. Alan Diehl, a former FAA crash investigator, emphasized that midair collisions often stem from failures of pilots to visually see and avoid each other.

Despite the mostly cloudy weather at the time, visibility was reported as good by AccuWeather, further complicating the investigation into this tragic incident.