Morris, 40, described as a builder and scrap metal dealer, has been portrayed as a drug-taker, and a man with a criminal past who was prone to violent outbursts.

Mr Morris denies all the charges

A father of two, he began living with girlfriend Mandy Jewell at Rhyddwen Road, Craig Cefn Parc, near Clydach, in 1995.

Halifax-born Mrs Jewell - Mandy Power's best friend - admitted to Swansea Crown Court that the relationship was often a tempestuous one.

She said that Morris would retaliate if pushed and shoved while arguing.

He began a secret affair with Mrs Power in 1998 - a sexual relationship which continued intermittently until the day before the murders, when they had sex in her bedroom.

Prosecution lawyers suggested he had killed Mrs Power and her family after she spurned his sexual advances.

He was portrayed as a man capable of violence. The jury was told that he had a long record of violent crime, including an attack on a woman.

I could see the hatred. He called her an evil bitch

Neighbour Janice Williams

It was heard that he once hit a man over the head with a length of wood, and was also jailed for offences including robbery and burglary.

And it was revealed that, 15 years ago, he was sentenced to four years in jail after lying in wait for a woman at the bottom of her garden, then throwing her over the bonnet of a car and snatching her handbag.

Morris' use of drugs became one of the key focuses of the trial.

A witness told the court he supplied Morris with amphetemines for injecting in the week leading up to the murders.

Bought drug

Terry Williams - a reformed drug user - said he supplied up to 6g of amphetamine power over several days.

Just hours before the killings, Morris bought 1.5g to 2g of the drug from him for �10.

The jury was told that the effect of the drug was to quicken the mind, and could leave users "psychotic" if deprived of sleep.

Friends who were drinking with Morris in a pub the evening before the murders said he became angry and irate as he talked about Mrs Power just hours before she died.

Janice WIlliams said : "I could see the hatred. He called her a ******* evil bitch".

She described his eyes as "wide and bulging".

Replacement

Evidence of Morris' lying provided further reason for the jury to doubt his credibility.

He lied about losing his gold chain - found in a pool of blood at the murder scene - denying that the one found at the house was his, and buying an identical replacement in order to avoid suspicion.

Deborah Morris outside Swansea Crown Court

Then, four days before the start of the trial, he changed his story and admitted the chain was his.

He also lied about the last time he had sex with Mrs Power - initially saying it had been some weeks before the murders, but later admitting it had been the day before.

However he continued to deny any involvement in the murders, saying he was walking to his mother's house when they happened.

Despite the guilty verdict, David Morris's family have continued to support him and have said he is already considering appealing against the conviction.

Morris's sister Debra said: "We are devastated by the verdicts.

"We are told by David's lawyers that there are good grounds for an appeal. We are confident that justice will prevail."