Air crash investigators and police are resuming efforts to establish the cause of a collision between a helicopter and aeroplane that left four people dead.
Two people were killed in each aircraft in Friday’s crash in Buckinghamshire. There were no survivors.
The Air Accidents Investigation Branch (AAIB) and police are to continue their work at the site of the crash at Waddesdon Estate, near Aylesbury.
The wreckage of the aircraft is scattered in a wooded area.
Investigations at the site are expected to continue for several days.
The helicopter and the Cessna plane both took off from Wycombe Air Park, also known as Booker Airfield, which offers flight training.
It is about 20 miles (30km) from the site of the crash.
No details of the crash victims have yet been released by police.
Thames Valley Police said the priority was giving information to the next of kin.
Emergency services were called to Upper Winchendon, close to Waddesdon Manor, at 12:06 GMT.
Mitch Missen, an off-duty firefighter, witnessed the crash from his garden.
He said: “I looked up and saw as both collided in mid-air, followed by a large bang and falling debris.
“I rushed in to get my car keys and en route called the emergency services, who I continued to give updates as to its whereabouts.”
Andy Parry, a teacher in Aylesbury, said he was with students at Waddesdon Manor at the time of the crash.
He said they heard a “massive bang” and saw debris in the sky.
A spokesperson for the National Trust-owned Waddesdon Manor said the crash had not happened in its grounds, but staff helped direct the emergency services to the scene.