Mrs Power had been subjected to a brutal and frenzied sexual assault, said the officer leading the murder hunt. She had tried desperately to defend herself from the attacker who may have been waiting for her when she returned home after baby-sitting at a relative's house. Forensic examination suggested she may have been the initial target.
Detective Superintendent Martin Lloyd Evans, heading a team of 50 officers, said "lively and bubbly" Mrs Power had been involved in male and female relationships since divorcing her husband Michael. A police spokeswoman said her bi-sexuality was disclosed in an attempt to open "all lines of inquiry".
Mr Evans said there was no sign of a forced entry at the semi-detached house in Kelvin Road. "There is every possibility Mandy was attacked in front of her girls before they too were bludgeoned to death with some form of heavy weapon."
The children were found upstairs in the four-bedroomed house. Their grandmother, asleep in bed in another room, was attacked with the same weapon.
Detectives have already questioned Mrs Power's ex-husband, who was with his new partner in Clydach at the time of the fire. He was said to be devastated.