Australian-born Brenton Tarrant has been formally charged with murder in a shooting rampage that left 49 people dead in two New Zealand mosques. Police said more charges will be filed against him. Three more people are in custody.

Brenton Harrison Tarrant, a 28-year-old Australian man, was charged with murder over the Christchurch massacre during a brief court appearance on Saturday. He did not request bail and was ordered to remain in custody until the date of his next hearing, scheduled for April 5.

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The investigation is led by New Zealand police and assisted by Australian police in New South Wales. NSW Police Assistant Commissioner Mick Willing told media that the region's joint counterterrorism unit has joined the investigation. Tarrant's relatives have been assisting the police as well.

Tarrant was escorted to a heavily-guarded courtroom under unprecedented security measures as agitated people flocked to the Christchurch District Court, even though it was closed to the public and only accredited media members were allowed in.

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There were calls by some people from the crowd to lynch Tarrant before the hearing.

Just as he was about to be brought into court, one person wielding a knife attempted to enter the courtroom, New Zealand Herald reported. The man reportedly told the paper that he wanted to stab the suspect.

“What the f*** has happened here,” he told reporters. Another man was cited shouting “rot in f****** hell” as he drove by the courthouse.

Tarrant reportedly hails from the town of Grafton, in northeastern New South Wales, but has been living in Dunedin, New Zealand, for quite some time, according to the reports in the local media. While in Australia, he worked as a personal trainer at a local gym in Grafton from 2009 to 2011, ABC reported.

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He is alleged to have penned a 74-page manifesto, titled "The Great Replacement" where he delves into what had inspired him to carry out the shootings and vows "revenge" against Muslim "invaders." The manifesto was reportedly written two weeks before the attacks. Tarrant also livestreamed his rampage online on Facebook. The footage in which he goes from room to room gunning down worshippers was promptly taken down on police request.

The manifesto suggests Tarrant harbors neo-fascist beliefs and draws inspired from other infamous shooters and conquerors of the past. His weapons bore neo-Nazi inscriptions and slogans, names of extremists, as well as historic figures who waged wars against Muslims.

Forty-nine people died in the Al Noor mosque and the Linwood mosque and over 40 were injured, some critically. In the wake of the attack, New Zealand Prime Minister Jacinda Ardern proposed an overhaul of the gun laws banning semi-automatic rifles. The suspected shooter held the "category A" firearms license since 2007.

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