Police say they believe that four people aboard a helicopter are dead after it crashed in Norfolk by Gillingham near Beccles.

The area was quickly taped off by emergency services, reports BBC News. The East of England Ambulance Service NHS Trust released a statement saying, "Sadly, it is believed that four people in the helicopter are believed to have died in the crash."

One witness, James Avery, near the crash site said he was outside when he heard the helicopter first take off while flying very low and then less than a minute later he heard what he assumed was a crash. "I heard a big bang followed by the sound of the turbine engine quickly stopping."

He and a friend went in search of where they believed the helicopter crashed, but were unable to locate it because of the heavy fog in the area.

Though it isn't known yet what caused the crash, fog is believed to have played a part, but it is still too early to tell, according to The Telegraph. A neighbor near the cordoned off area said, "It's so foggy out there you can barely see anything."