The Clydach murders trial jury has resumed for its fourth day of deliberations at Newport Crown Court.
David Morris denies the "massacre" of Mandy Power and her family
Three generations of the same family were beaten to death in their Swansea Valley home in June 1999.
David Morris, 44, from Craig-cefn-Parc, denies murdering Mandy Power, 34, her daughters Katie, 10, and Emily, eight, and their grandmother Doris Dawson.
The jury began deliberating on Monday morning after hearing evidence since the retrial began 13 weeks ago.
The victims' bodies were found by firefighters alerted to a blaze, which Mr Morris is alleged to have set at their home in Kelvin Road, Clydach.
Summing up on Friday, the judge told jurors that "words could not convey" the severity of the victims' injuries.
Their skulls had effectively been smashed with a four-foot fibreglass pole.
He said there was also a "terrible possibility" that one of the children had brought in the pole to try to save the life of her mother from the attacker.
Last Thursday, at the start of his summing-up, he told the jury they had probably seen the killer in the court room.
Mandy Power's two daughters and her mother died with her
They had to consider, he said, whether the person responsible for the killings was the defendant, or Ms Power's lesbian lover, Alison Lewis, perhaps helped by her then husband, a serving police officer.
The prosecution has claimed that David Morris was responsible for the murders while "fuelled by drink and drugs...he committed the worst kind of massacre and sought to destroy the evidence".
But the judge also outlined to the jury that the defence claimed Mr Morris was elsewhere at the time of the murder and that "they suggest the police had probably got it right in July 2000 when Alison Lewis was arrested on suspicion of murder... perhaps assisted by Stephen Lewis [her husband]".