"POSSESSIVE", "controlling", "obsessively jealous" - just a few of the words used to describe Carl Mills as he stood trial for the murder of his girlfriend, their baby daughter and his girlfriend's mother.
Originally from Bolton in Greater Manchester, Mills, 28, met Kayleigh on social media site Facebook in August 2010 and began making the trips to Cwmbran to be with the teenager, then aged 15.
Mills said he then moved down to the area full-time in July/August 2011 and lived in the Buckley home.
Prosecuting barrister Gregory Bull QC told the court how Mills had set out to "groom her sexually", and a relationship developed with Kayleigh becoming "infatuated" with the defendant.
Mills' controlling behaviour led to Kayleigh playing truant from school and he allowed her to run away from home to sleep rough with him in the streets.
This led to Kayleigh losing contact with her friends.
Friend of the family, Louise Davey told the jury: "He was possessive and controlling with her.
"She wasn't allowed any friends. She wasn't allowed to go out."
But despite many of Kayleigh's family and friends being against the relationship, she fell pregnant with twins.
Baby Angel was stillborn in March last year after being born at 24 weeks, while baby Kimberley battled health issues, including breathing problems, a heart problem and trouble with feeding during a six-month stay in hospital.
Despite his new responsibility, Mills' attitude didn't change.
He admitted that he had a drink problem and would turn up drunk at the hospital.
This led to him only being allowed supervised access with the baby.
At a meeting at the hospital regarding the discharge of his baby, neonatal liaison nurse Fran Harries described how he didn't participate or show any interaction.
Friend of Kim Buckley, Regina Pritchard, told the jury: "Kayleigh wanted to bond (with Kimberley), but Kim said he wouldn't let her. He was jealous."
She added: "All he wanted was Kayleigh."
Mills, an only child who was brought up by his mother in Bolton, did have a number of chances given to him to change, but did not take them.
He was offered counselling sessions for his drinking, but alcohol therapist Darren Fewins, who described Mills as an "episodic drinker" said Mills turned up late to three appointments before telling them he no longer required the service.
Kim Buckley offered him the chance to stay in the family home one night in August while she and Kayleigh were at the hospital, but he cut electric wires to the television and fish tank and allowed the dogs to mess the house.
Following this, Ms Buckley changed the locks to her home, but after Kayleigh bought a tent which was put up outside the front of the Buckley home, this became Mills' new home with Kayleigh also sometimes spending time in there with him.
Abusive text messages and Facebook messages were also sent by Mills to both Kim and Kayleigh, the court heard.
He told Kim Buckley he was going to "fire her off the face of this earth" and threatened to burn her house down and "cut her up" while she slept.
Mill, whose only job had been at a woodyard around the age of 16 or 17, even told her he was going to stab Kayleigh "with the babies inside her".
With Kayleigh. he demanded a DNA test in relation to the baby and threatened to dig up his dead baby's grave.
He also told her a few weeks before the fire that he would be going on "a murder mission" and that he was going to kill her.
On the evening of the fire, the threats continued with Mills sending a text to Kayleigh stating: "I hate you. I hope you ******* get burnt."
Even after the crime had been committed, the court heard Mills remained calm at the scene, even at one point telling arresting officer Police Constable Daniel Wise that his girlfriend and baby child were in another house.
PC Wise told the jury he had found Mills in the back garden of the home at the time of the fire, and said Mills, who appeared drunk, was shouting for his girlfriend and child and said he thought they were in the house.
But after PC Wise had informed a fire officer, he said he then returned to Mills to ask him if he knew where in the house they would be.
Mills then told him that he thought they weren't in that house, but in another house and pointed to a row of houses behind the Buckley home.
When arrested on suspcion of arson with intent to endanger life. Mills asked: "What have I done?"
PC Natasha Counsell. who was also at the fire scene and saw Mills in the garden, said: "He appeared calm, he was just talking to me as if he was talking about the weather.
"He didn't appear concerned at all "
When he was later rearrested on suspicion of murder, Detective Sargent Stu- art Crocker told the court how Mills replied: "I didn't do nowt.
"I was trying to get in through the back door.
"The police arrested me because they thought I done it."