Three men and a woman deny the murder of Terry Oldham, 63 in Camborne, Cornwall as well as allowing the death of a vulnerable adult.
Truro Crown Court heard it was the "culmination" of a series of attacks and abuse by the defendants.
Mr Oldham's body had fractured ribs, and bruises around his sexual organs.

Aaron Mallon, 24, and Michelle Casterton, 43, both of Grenville Road, Falmouth, Daniel Quinn, 23, of Tregullow Road, Falmouth and Richard Rosevear, 32, of Truro Road, St Austell, all shared a house with the victim.
The court heard one of the defendants boasted of stealing money from Mr Oldham's account and another said they had fed him a curry made from dog faeces.
Sometimes they would not let him out of the house or use the toilet "until it was too late", the jury heard.
Paul Dunkels, prosecuting, said the group had discovered he was a sex offender from written material found in his room.
In 1987 Mr Oldham was convicted of indecent assault on a girl under 14.
"They regarded him as fair game because he was a convicted sex offender," said Mr Dunkels.

'Fear of retribution'

He told the court Mr Oldham "was a small frail man routinely bullied by the defendants who took his money and possessions".
At 06:44 on 1 April the ambulance service received a call from Ms Casterton who said she thought Mr Oldham was dead.
Mr Dunkels said: "It was obvious to the paramedic that Oldham was dead.
"It must have been obvious he was seriously ill but no-one went for any help until he was dead."
Mr Oldham had few friends and was reluctant to talk about his injuries out of fear of retribution from the defendants, he added.
He was found dead at Dolcoath Road, Camborne on 1 April 2014.
The trial continues.