Detectives have launched a murder inquiry after a 64-year-old man was found battered to death at his home.

The victim was found fully clothed and slumped on his blood-stained bed at his top-floor flat in Lower Rock Gardens, Kemp Town, Brighton.

Friends and neighbours, who knew the victim as Billy, expressed shock and anger.

One said: "He was a total softy who wouldn't harm a fly. What has happened to him is sick."

The victim suffered serious head wounds, thought to be from repeated blows with a heavy object.

A post mortem carried out last night showed the victim suffered a severe beating and had wounds all over his body.

The victim was gay and police have not ruled out the possibility this was a homophobic attack. He was also a drinker and would invite other drinkers back to his rented Regency flat.

His body was discovered yesterday morning when friends became concerned. They had not seen him for some time and decided to force their way in. They discovered the body and immediately alerted police.

A full-scale investigation was launched, led by Detective Chief Inspector Jim Torbet of the Sussex Police crime and drug unit. An incident room has been set up at the John Street police station.

Scenes of crimes officers carried out a fingertip search of the flat and police are also studying footage from a street camera.

The man's best friend arrived at the flat yesterday afternoon to find police standing guard outside.

Vincent Bennett, of High Street, Kemp Town, wept when detectives broke the news.

He said: "I've known Billy since 1982 when we used to be waiters in restaurants in the town. He was a lovely man who would not harm a fly."

A 36-year-old man has been arrested in connection with the murder but police stressed their inquiries are "very much ongoing".

Forty detectives and uniformed officers were today working on the case.

Police spokeswoman Carolyn Bond, said: "We still have no definitive cause of death and further tests are being carried out."

Mr Torbet said: "This was a brutal attack on a man described by friends as friendly and nice. We urgently need assistance from the public to identify the culprit."

Police appealed for witnesses who may have seen the victim after 2pm on Sunday or saw anything suspicious in or around his home to come forward.

They said the killer's clothes may well have been bloodstained.

Mr Torbet said: "We are following up a number of strong leads but we need to speak to anyone who saw anyone going in or out of the flat in Lower Rock Gardens."

Anyone with information should contact the incident room on 01273 665626.