The aircraft came down in near Gillingham, near Beccles in Norfolk on Thursday evening.Emergency crews were called to the crash scene at 7.30pm after members of the public heard the noise of a loud crash.Norfolk Constabulary were deployed to locate the crash site with assistance from a police helicopter.All four occupants on board the helicopter were pronounced dead at the scene, police said.Inspector Louis Provart said: "Emergency services are working together in difficult conditions to secure the scene and carry out an initial investigation into the circumstances."Our thoughts are with the family and loved ones of those who have sadly lost their lives this evening.Inspector Louis ProvartPolice said the crash site was located in a field containing some wooded area."Next of kin are currently being informed and no further details of the deceased will be released until this has been carried out," police added.Officers remained at the scene on Thursday night."A cordon is in place while police investigators carry out initial enquiries and the Air Investigation Branch has been informed," Norfolk Constabulary said.A spokeswoman for East of England Ambulance Service said: "Ambulance resources have now been stood down from the scene. Our thoughts are with the family and friends of those who have lost their lives."A spokesman for the Air Accidents Investigation Branch said it will be sending a team to investigate.