Man killed by 'someone he knew': police

A man whose body was found in a Sydney stairwell seven years ago was killed in a "callous attack" by someone he knew, police say.

On the seventh anniversary of Hugo Fifi's death, police have appealed to the public for help to close the case.

Emergency services were called to a unit block on Fullagar Road in Wentworthville about 3.45am on April 18, 2009, where they discovered the 48-year-old's body in a stairwell.

It's believed Mr Fifi was assaulted at a unit block in Westmead beforehand, police revealed on Monday.

Investigators have retraced his steps that night, starting with a dinner in Guildford followed by a visit to a friend in Westmead Hospital.

Mr Fifi then drove to a unit block on Central Avenue in Westmead about 9.30pm, where it's believed he was assaulted, then caught a taxi to Wentworthville where his body was found.

He pressed a number of buzzers to try and get into the unit, believing he knew people who lived at the unit block.

"He was there seeking help," Holroyd crime manager and Detective Acting Inspector Des Wilson told reporters in Parramatta.

"It was a callous attack."

Police are keen to talk to the taxi driver, who hasn't yet been identified.

Mr Fifi's car was dumped in Northmead by an unknown man as his body was found.

"Whether he had direct contact with Mr Fifi or not, it is clear this man has some knowledge of the circumstances surrounding his death," Det Act Insp Wilson said.

He's described as being of Mediterranean/Middle Eastern appearance, aged in his 20s, about 183cm tall and he was last seen wearing a hooded jumper and jeans.

Co-operation of key witnesses has allowed police to make significant progress, police say.

Mr Fifi's nephew also appealed to the public for help while paying tribute to his uncle.

"He was a kind and caring man who would do anything to lend a helping hand, even to strangers," he said.

"He was taken from us ... It is simply not fair."