Becky Watts trial: Nathan Matthews - a profile

He stood as a pained figure, and sobbed often and loudly in the witness box, as he attempted to defend his acts of evil. Nathan Matthews claimed he merely wanted to teach his step sister a lesson, to stop her from being disrespectful to his mother Anjie Galsworthy.

But it was an explanation neither the police, nor the jury, believed - telling a court they instead thought he was guilty of not only murdering his own step-sister, but butchering her dead body in a macabre crime.

Bristol Crown Court heard Matthews had a “reasonably normal” childhood, living with mother Anjie before his grandmother, Margaret May, took over care. He would see his mother often however, and she would frequently walk him to and from school.

He was a keen participant in the army cadet force, and rose up through the ranks quickly. He later joined the Territorial Army, but left soon after claiming he couldn’t cope physically, and didn’t like the inequality of treatment.

At the age of 21 a shy and reserved Matthews, who suffered with anxiety and found it difficult to talk to others, met 15-year-old Shauna Hoare and they began a relationship. In every outward sense, they were a happy couple, and Matthews a grounded and happy individual.

But there was a more sinister side to the now 28-year-old. One that would snap frequently, often losing his temper, punching a wall at the doctors out of frustration, and on some occasions even lashing out at Hoare.

By his own admission he had anger problems, telling the court if he was shown violence he “would show it back”, and urged people not to “back a rat into the corner”.

Matthews would also, according to Becky’s best friend Courtney, often graphically describe how he would kill his step-sister, something the 17-year-old said would worry Becky.

Matthews made no bones about how he felt towards his step-sister, calling her selfish and spoilt, often telling his girlfriend and mother of his feelings. It was these that lead to the unimaginable outcome, the self confessed “emotionally unstable, psychologically disturbed, metrosexual neanderthal” eventually snapped.