Former scrap metal dealer David Morris, 39, from Craig Cefn Parc in Swansea Valley, Wales, denied four charges of murder, but was found guilty and given for life senrences.
Mrs Power, 34, her invalid mother Doris Dawson, 80, and daughters Katie, 10, and Emily, eight, were found battered to death at their home in Kelvin Road, Clydach, Wales in June 1999.
The prosecution alleged that Mr Morris carried out the killings after his sexual advances were rejected by Mrs. Power.
Passing sentence Mr Justice Butterfield told Morris: "These were horrific murders committed with great savagery in which you inflicted appalling injuries on innocent victims. You've shown not a trace of compassion or sympathy."
Morris showed no emotion as he was led away from the dock, but shouts of abuse could be heard from the public gallery. The jury had heard how the 27 June 1999 massacre at Kelvin Road, Clydach, south Wales, began when Mrs Power rejected Morris's advances for sex.
They heard that Mrs Power had begun a lesbian affair with a former policewoman and did not want to sleep with him again. Morris flew into a rage and embarked on what the jury heard described as an "orgy of savagery". Patrick Harrington QC, prosecuting, said Mrs Power alone had been beaten 38 times with the murder weapon. Doris Dawson was murdered as she lay in bed. Morris then set her body alight. One of the children's bodies lay on the landing. Another was found in their bedroom, still in a cowering position.
David Morris was caught after a bloodstained gold necklace, ripped from his neck during the murders, was found in the victims house by forensic scientists.
Paint found on the jewellery exactly matched paint found on kitchen units at Morris' home.
In police interviews, he insisted the chain did not belong to him - only to later change his story and admit it did. The jury had been told that Mrs Power had spoken about how much Morris frightened her, and had previously been beaten by him.
The trial judge, Mr Justice Butterfield, ruled the jury could be told about Morris's almost two dozen previous convictions for robbery and violence.
Three other people originally arrested over the murders are to sue the force for damages.
About a year after the murders, Mandy Power's lesbian lover Alison Lewis was arrested on suspicion of the murders. She was held along with her then husband, police sergeant Stephen Lewis, and his brother Inspector Stuart Lewis. All three were later released without charge.
It was not until March 2001, that South Wales Police confirmed that Morris had been arrested. Speaking outside the court after Morris's sentencing, Mrs Lewis said she was satisfied justice had been done, but complained about her treatment.
"While standing trial for murder, the judicial system afforded David Morris the luxury of being innocent until proven guilty. "Throughout the trial my rights as an innocent person were neither given nor respected as David Morris's defence team did their utmost to make me look guilty by implication and insinuation," she told reporters.
However, as the police van carrying Morris sped off, some of his friends shouted "the wrong one went in the van". His sister Deborah said: "We are devastated by the verdict but we are unable to understand the evidence that was presented to the court.
"We are told by David's lawyers that there are good grounds for an appeal. We are confident that justice will prevail."
Mrs Power's brother, Robert Dawson, spoke of the "sheer horror" his family had been through and said the guilty verdict would "never be enough" to relieve their pain and loss, although he was relieved the killer was behind bars.
20th March 2003
Morris lodges an appeal against his conviction.
Judge Mr. Justice Nelson spent weeks studying the papers submitted by Morris' lawyers in his defence. He has decided that there are no grounds to take the case to appeal.
