The man convicted of battering to death four members of a family had a history of violence and a list of previous convictions running to four pages.
Labourer David Morris, 44, has also been portrayed as a drug-taker and a man prone to violent outbursts during the three month murder retrial.
This is the second time Morris has been found guilty of the murders. His 2002 convictions were quashed on appeal.
The conviction brings an end to a tumultuous seven year investigation.
Morris' string of previous convictions include robbery and burglary, for which he spent time in jail.
He also once hit a man over the head with an iron bar and a hammer and in 1987 he was sentenced to four years in jail after attacking a woman and snatching her handbag.
Morris, a father of three and a grandfather, has been found guilty of battering to death Mandy Power, 34, Katie, 10, Emily, eight, and Doris Dawson, 80, in their home at Clydach, south Wales, in June 1999.
His original convictions for the murders were quashed in 2005 after he lodged an appeal.
Some people living in Clydach area have said they had long been aware of his violent reputation.
Councillor Sylvia Lewis, who knew his victims, described Morris as evasive and dangerous - a man who frightened the entire community.
"He was an aggressive, violent person who could explode at any moment. People were petrified of him," Ms Lewis told the BBC.
"I think the elderly people in Craig Cefn Parc (Morris' home) can sleep in their beds at night now."