MURDER accused Carl Mills is a "pathological liar" and a "calm and determined killer" the prosecution claimed today during closing statements in the Cwmbran triple murder trial.

Mills, 28, denies killing his fiancee Kayleigh, 17, her mum Kim Buckley, 46, and the couple's six-month-old daughter Kimberley in a fire on September 18 last year.

Prosecutor Gregory Bull QC told a jury at Newport Crown Court during closing speeches: "[During the opening] It was the Crown's case that Mr Mills had murdered three people. That is still the case."

"We urge you to the view that not only can you be sure that he lit the fire, but that he did it unlawfully and that he did it intending to, at the very least, cause serious harm to one of the residents in that house.

"It does not matter whether he intended to harm Kim, or Kayleigh, or Kimberley, the fact that he intended to harm somebody in the house, even his imaginary fourth person - the boyfriend he was accusing Kayleigh of having an affair with. If you intend to kill anybody inside a property you are guilty of killing them all if death results."

Mr Bull QC said experts agreed the blaze at 15 Tillsland was started deliberately, most likely with the application of a naked flame to materials in the porch, although one said he could not rule out that it wasn't started by a discarded cigarette.

Mr Bull said the jury had to take text messages sent by Mills to Kayleigh threatening to burn down the house the night before the fire into account when deciding if he was guilty or not.

He said: "It's farcical to suggest that some other stranger has come along after all that history and just happens to deliberately light a fire at about three o'clock in the morning.

"It's a nonsense, with respect, to suggest the fire was started by a carelessly discarded cigarette, presumably by Kayleigh, or some other person came and happened to drop a cigarette in that particular porch, at that particular time after these messages have been sent.

"We suggest there is powerful evidence that, in fact, this defendant wasn't at the Mill Tavern when he saw smoke and heard screams, he was at the brick."

"The truth is he lit that fire and went a short distance away to the brick where he could watch his handiwork unfold - the actions of a calm and determined killer."

Mr Bull said Mills was not the "doting" father figure he liked to portray and claimed he had repeatedly lied to police and the jury to mislead them into thinking he was a caring lover.

He said: "Carl Mills is not capable of telling the truth about anything. You can believe him when he says his name is Carl Mills - in terms if anything else he is a pathological liar."

Proceeding