According to reports, 63-year-old Terry Oldham was convicted in 1987 of indecently assaulting a 14-year-old girl and had been placed on the sex offenders register.
Aaron Mallen, 24, Michelle Casterton, 43, and Daniel Quinn, 23, and Richard Rosevear, 33, moved in as Oldham’s housemates.
When they discovered his past, they decided he was “fair game”.
Speaking in Truro Crown Court, prosecuting lawyer Paul Dunkers listed a series of “extensive injuries”, which showed that elderly Oldham had been assaulted over an extended period.
“He (Mr Oldman) was a small frail man in his 60s. He was routinely bullied and assaulted by them, they took his money and they stole his possessions,” he said.
"Terry Oldham became increasingly isolated and depressed as the defendants took over his house and his life."
From allegedly forcing him to eat dog faeces, to refusing to let him leave to go to the toilet, the defendants constantly inflicted abuse upon the elderly man.
A post mortem revealed that they had sexually assaulted him with a broom.
This caused Oldham to suffer internal injuries and poisoning which led to organ failure.
The prosecuting lawyer told the court it had been “obvious” to the defendants Oldham was “seriously ill but no-one went for any help until he was dead."
The trial continues.