A new television drama has put one of Britain’s most infamous criminal cases back into the spotlight after 35 years. The man convicted of killing five members of his own family has always maintained his innocence – but what are some of the key evidential issues in the White House Farm case?
ITV's new six-part series - White House Farm - is retelling the true story of how 24-year-old Jeremy Bamber murdered his adoptive parents, sister and nephews near Tolleshunt D'Arcy in 1985.
Bamber's parents Nevill and June, both 61, were shot, along with his model sister Sheila "Bambi" Caffell, 26, and her six-year-old twins Daniel and Nicholas at White House Farm during the night of August 6-7, 1985.
The police and media initially believed a murder/suicide theory that Sheila, who had mental health problems, had killed the members of her family before turning the gun on herself.
But attention soon turned to Bamber, who stood to inherit around £435,000 following the deaths of his family members.
He was convicted of the killings by a jury at Chelmsford Crown Court on October 28, 1986, and currently remains in prison in Wakefield, Yorkshire, serving a whole-life tariff.
Bamber has appealed his conviction several times and the case has been subject to reviews by the Criminal Cases Review Commission.
Essex Police say there has never been any evidence to suggest he has been wrongly convicted.
But what are some of the key issues argued by Bamber's defence at trial and by his campaigners fighting to secure his release?
Silencer
One of the key arguments was whether the gun had a silencer on it when the murders were committed. It was crucial to the prosecution's case because with the silencer, the .22 Anschütz semi-automatic rifle was too long for Sheila to have shot herself. Forensic tests indicated that Sheila's arms were not long enough for her to have turned the gun on herself if the silencer was attached.
The silencer was not found by police, but was discovered three days after the murders by one of Bamber's cousins in the gun cupboard.
Police were not immediately alerted, but the silencer was collected on August 12 and when analysed, it revealed blood on its inside and outside surface.
The outside sample was not enough to allow analysis, but the blood on the inside was discovered to be the same blood group as Sheila's - although could have been a mixture of Nevill's and June's.
The prosecution argued that if Sheila had shot her mum, dad and sons with the silencer, then realized the gun was too long to shoot herself, the silencer would have been found next to her body.
The former model had no reason to return it to the gun cupboard before going back upstairs to shoot herself, the prosecution said.
In 2012, Bamber's lawyers commissioned experts to examine crime scene photographs and silencer evidence. They argued that injuries on the bodies were consistent with the silencer not being used.
They also argued that the absence of the silencer would explain three circular burn marks, which had been found on Nevill's back.
In her book, The Murders at White House Farm, author Carol Ann Lee writes: "No-one is able to satisfactorily explain the burn marks on Nevill's back."
MORE: What is the true story behind the White House Farm murders in Essex? The crime scene
Following the murders, the crime scene was not secured properly, and the house was not searched thoroughly.
After the verdict, the media did not hold back in its condemnation of Essex Police. The Times wrote about "Blunders, omissions and ineptitude", while The Daily Mail referred to "The Clouseau Squad" of detectives in the case, Lee said in her book.
DCS James Dickinson led the internal review and his 300-page report expressed regret that DCI Thomas 'Taff' Jones - who died before the trial started in 1986 and believed Bamber innocent - was no longer able to "account for his decisions".
The defence argued that the first officers to enter the farmhouse had disturbed the crime scene - and then reconstructed it.
Scratch marks
In a 2010 report from a forensic photographic expert, commissioned by the defence, the argument was made that scratch marks in the red paintwork on the kitchen mantelpiece had been created after the crime-scene photographs had been taken.
The prosecution argued that the marks had been made during the struggle in the kitchen between Bamber and Nevill as the silencer scratched against the mantelpiece.
Paint chips identical to the paint on the mantelpiece had been found on or inside the silencer, according to the prosecution.
But the expert argued that the scratch marks appeared in photographs taken on September 10, 1985, but were not seen in the original photographs.
He concluded the marks had been created after the day of the murders.
MORE: Jeremy Bamber: 'My personal opinion is very much that he's guilty' - author Carol Ann LeePolice logs
Another key prosecution argument was that Nevill Bamber did not call the police. Bamber has always claimed his father called him to say Sheila "had gone beserk" with the gun and campaigners say a telephone record shows that Nevill also called police that night.
Bamber's campaigners claim Nevill's telephone call was made at 3.26am - ten minutes before Bamber called Chelmsford Police Station.
A separate log of a police radio message revealed there was an attempt to speak to someone inside the farmhouse that night, as police waited outside to enter, but there was no response.
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