Hayden Miles murderer's appeal fails

The man who murdered and cut up Christchurch schoolboy Hayden Miles has lost his appeal against his conviction and sentence.

Gavin Gosnell was found guilty of Hayden's murder after a trial in the High Court at Christchurch last year.

He was sentenced to life in prison with a minimum non-parole period of 18 years.

Gosnell, 29, appealed against his conviction and sentence in the Court of Appeal on a number of grounds, including that he wanted to give evidence but felt pressured at the last minute not to and that the prosecutor's emphasis on Hayden's dismemberment had an insurmountable prejudicial effect.

In its decision, the Court of Appeal said Gosnell's lawyer Craig Ruane handled a difficult trial with commendable professionalism and did not believe Gosnell was pressured not to give evidence. It also found that while the evidence about Hayden's dismemberment was shocking, the Crown did not make more of it than was fair.

Gosnell admitted killing Hayden, 15, after a prolonged assault at a Cashel St flat on August 22, 2011.

Gosnell then cut the schoolboy into 12 pieces with a $20 jigsaw. He dumped the remains in two city graveyards and buried the organs in the backyard.

He denied murderous intent at his trial and asked to be convicted of manslaughter.

Watch: Gone but not forgotten: A tribute to Hayden Miles