A white supremacist who killed 51 people at two New Zealand mosques has appeared in court to try and withdraw his guilty plea.

Australian Brenton Tarrant is serving a life sentence with no parole after admitting to murdering the 51 people and attempting to murder another 40 in the March 2019 attack on worshippers during Friday prayers in Christchurch.

He initially denied the charges, but changed his plea a year after the attack. The 35-year-old, who also admitted one count of terrorism, has now launched an appeal, filed out of time, arguing he was incapable of making rational decisions at the time because of torturous and inhumane conditions in prison.

He also wants to appeal against his sentence. The hearing at New Zealand's Court of Appeal in Wellington is scheduled to run all week, with Tarrant expected to give evidence via video link.

Victims and family members will be able to watch the hearing via a delayed broadcast. Among those planning to attend is Aya al-Umari, who lost her older brother Hussein in the attack on Al Noor mosque.

I very distinctly remember that I left court after the sentencing thinking 'Right, the trauma chapter is now closed, time to heal, time to focus on your own mental well-being', but then it pops up again and again, al-Umari told the BBC.

It will be just an image that I am looking at, because he means absolutely nothing to me at this stage. I suspect one of his main motivations to do this is to open up traumas again and I won't let him succeed in doing that - he just wants his limelight and to be relevant again.

Hussein al-Umari was awarded a New Zealand Bravery Star for standing up to Tarrant. He took the right of life of my brother and 50 others, and then we're going to sit through now and talk about the legal arguments of his right to appeal, al-Umari said.

If the three appeal court judges decide he can withdraw his guilty plea, the case would potentially go to trial on all charges. If he is not allowed to retract his plea, there will be another hearing later in the year to consider his appeal against his sentence.

Tarrant was born in New South Wales, Australia, but moved to New Zealand in 2017 - which, prosecutors said, was when he started planning his attacks against the Muslim community. He was active on fringe online forums and before the attack, he had posted a 74-page manifesto online.

The massacre prompted New Zealand to pass stricter gun laws and buy back certain types of weapons from owners. Within a month of the shootings, the country's parliament had voted overwhelmingly to ban military-style semi-automatic weapons and the government offered to compensate owners of newly illegal weapons in a buy-back scheme.

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