Nikitta Grender's father said he was shocked at the sentence handed down to a distraught friend of the murdered Newport teenager.

Luke Morgan, 22, caused up to £9,000 worth of damage when he set fire to his mum's Newport City Homes-owned Broadmead Park home in the early hours of October 18, 2012.

He set fire to his home because he wanted to be with her and was yesterday jailed for three years because he was deemed too high risk to be dealt with in the community.

Nikitta's father Paul Brunnock said: "At the end of the day everyone's got to be punished for what they have done but I think that's a bit harsh.

"I am quite shocked, I thought they would have tried to help him rather than lock him away. I don't think that will help him at all."

An earlier hearing heard Morgan was upset after recent arguments with his mother and started to feel down when looking at photos of Miss Grender, 19, who was raped and murdered by Carl Whant in February 2011. He also killed her unborn baby Kelsey-May.

On Monday, Judge David Wynn Morgan told him he was considering a community sentence after doctors said prison would be detrimental to Morgan's mental health.

But today he jailed him for three years because the agencies responsible for Morgan did not have full confidence they could manage the risk he poses outside custody.

Morgan pleaded guilty to arson, being reckless as to whether life would be endangered at a hearing in January.

He told police on arrest he started the fire because he wanted to die, saying: "I don't want to be here, I just want to be with Nikitta."

Morgan lit a coat hanger using a cigarette lighter and put it in a recycling box, which ignited around 5.04am.

The court heard he planned to stay in the house but panicked when the fire spread and woke a neighbour who called dialled 999.

The family dog, which was in the house at the time, died in the blaze.

This is the second time Morgan had set fire to the house, having received a 12-month community order for arson in August 2011.

That time he set fire to curtains while his mum and siblings were inside the home, but they managed to get out safely.

SUE Ferrier, defending, said his behaviour was brought about by the traumatic loss of his dear friend and doctors say he is suffering post traumatic stress disorder.

She said he had made significant progress since being transferred from prison to a secure mental health hospital and doctors and asked if he could serve his sentence in the community.

Judge David Wynn Morgan adjourned sentence on Monday to investigate whether this was possible, but yesterday he agreed with the concerns of the probation service, which said Morgan was a high risk to the public.

He said: "The second offence of arson in 18 months was extremely serious endangering the lives of those living adjacent to his motherÕs property, committed against a background of severe personal stress and abuse of alcohol.

"Mr Morgan can only be managed safely in the community if those responsible for his care have full confidence in their ability to carry that out.

"They do not have full confidence that the risk Mr Morgan poses can be managed yet outside closed custodial conditions."

He was sentenced to three years and ordered to pay a £120 victim surcharge.