Bijan Ebrahimi, 44, took photographs of local youths attacking his hanging baskets and intended to hand the film to police as evidence.
SEARCH: Police looking for evidence after Bijan’s death
But someone saw him with the camera and told police that Bijan, who was registered disabled and couldn’t work, had taken pictures of children.
Officers took him away for questioning, but as Bijan was taken from his council flat residents began chanting “paedo, paedo”.
He was quizzed at a police station but officers soon realised he was using the images to catch local yobs.
Bijan was released from custody but rumours had begun circulating in the local community that he was a child abuser.
TRAGIC: The spot where Bijan’s body was found burned
The pair will be sentenced for the brutal crime next month after entering guilty pleas at Bristol Crown Court.
Speaking after the hearing, Avon and Somerset Police spokesman Martin Dunscombe said Bijan was an innocent man.
He said: “Mr Ebrahimi was arrested on suspicion of a public order offence – breach of the peace – and after being interviewed he was released with no further action taken.
“We can categorically state he had not taken any indecent images and that nothing of concern had been found on his computer.”
In a family statement his relatives said Bijan was a “loving and caring man” who lived for his garden.
They said: “Bijan was a quiet, disabled man whose only joys in life came from his horticultural interests and his cat.
“Bijan was a caring, loving and unselfish man. He was an excellent uncle and a warm, supportive brother.” It is also believed that he was subjected to harassment by “angry mobs” in the days leading up to his death.
Bijan Ebrahimi was initially arrested and released on July 12 and was killed in the early hours of Sunday, July 14.
One resident, who wanted to remain anonymous, said: “On the Thursday evening (before his death) everyone came out and they were calling him a paedophile.
“They had him down as a 100 per cent paedophile.When the police took him away everyone was cheering. Then he got released back into that.”
Another resident added: “Whoever started those rumours now has to live with that. He wasn’t a paedophile and he’s now dead.”
Neighbours described how Mr Ebrahimi had a passion for the flowers and plants he grew in front of his maisonette in Bristol and that he was “always out there” tending to them.
But after youngsters started destroying his beloved garden he began started taking pictures to hand over to the council, who owned his property, and the police.
Lee James, who pleaded guilty to murder, and Stephen Norley, who admitted to assisting an offender, decided to “take the law into their own hands”, a court heard.
Both the Independent Police Complaints Commission and the local council have now both launched a review into the way the case was handled.