Bombmaker Sean Nicholas, who caused evacuation of Auckland’s Albert Park, pleads guilty

A homeless man who caused the evacuation of Auckland's Albert Park last month had warned police he had "enough explosive material to level the Sky Tower" and was intending to detonate it as soon as the popular city centre park was cleared.

Police, for good reason, took the threat seriously. Sean Clifford Nicholas, 52, was known to police as a former bank robber and amateur bomb maker who had only recently been released from prison.

Nicholas pleaded guilty to the Albert Park charge earlier this month and appeared in Auckland District Court via audio-video feed again on Monday, hoping to receive an immediate sentence amounting to time served.

Judge Peter Winter, however, put the brakes on the process. He said he wanted to first see a pre-sentence report - anything that might help shed light on the defendant's "unusual tendencies".

The 24 January incident, which caused widespread disruption in the city centre as roughly 60 police officers from two districts rushed to the scene, occurred just two months and two days after Nicholas had been released on parole from his most recent prison sentence.

Court documents released to the Herald state Nicholas had in that time acquired items "intentionally selected to resemble" improvised explosive devices, or IEDs.

"The defendant chose the [Albert Park] location as it would allow maximum exposure," authorities said, explaining that Nicholas called a police officer known to him around midday and announced his plan to detonate the material.

The park, which borders both the University of Auckland and Auckland University of Technology main campuses, was cleared and nearby buildings were evacuated. Police were joined by firefighters, paramedics and an Army explosive ordinance disposal unit.

Over the next four hours of negotiations, Nicholas "continued to manipulate his assortment of items to appear as though he was assembling a bomb", court documents state. But police and firefighters gave up the talks and took "affirmative action" after he began to ignite an unknown liquid that was on him, authorities said.

"An examination of the defendant's items found it to contain a slurry of various liquids including isopropyl alcohol and deck varnish," the summary of facts for the case states. "These liquids were found to be flammable, however they would not have resulted in an explosion occurring."

After his arrest, Nicholas said he had left his court-ordered post-release residence and had been sleeping rough in a reserve behind the New Lynn WINZ office, where he claimed to have stored other IEDs. A subsequent police search of the reserve resulted in the discovery of various chemicals and five "thermos-type containers ... taped up with an unknown liquid inside" that "appeared to be IEDs".

An explosive disposal unit tested the items and found them to be flammable but not explosive.

"In explanation, the defendant stated he had other explosive devices hidden in a bush in New Lynn," court documents state. "He expressed the desire to offend by way of IED so he can be shot by police."

Nicholas' extensive criminal history dates back at least a decade, including a 2013 incident in which he was sentenced to prison after entering an Ellerslie bank with what turned out to be an air pistol and making threats.

In 2015, he was convicted of entering the New Zealand Stock Exchange with a knife and threatening to blow up the building.

He was sentenced two years later for returning to the same highrise where the bank incident had taken place - this time demanding to speak to someone at a chemical company based out of the same building.

"You said you had a bomb in your suitcase and you would blow yourself up and all the buildings in the area," High Court at Auckland Justice Timothy Brewer noted during the sentencing for that incident. "You added that the bomb was set to a timer which could not be altered."

More than 100 workers were evacuated from the building and when police approached he lit a wick protruding from the side of the suitcase, court documents state.

"The wick started burning. But it stopped when it reached the side of the suitcase," Justice Brewer noted at the time. "...You said that you had prepared and placed chemicals in the suitcase with the intention of blowing both yourself and the building up.

"A police bomb expert formed the view that the fuse in the suitcase would not have achieved your intended purpose, but, if introduced to a significant heat source, the contents of the suitcase had the potential to burn and emit toxic fumes."

The High Court was told in 2017 that Nicholas is confined to a wheelchair because of fibromyalgia, which causes continual pain. But Justice Brewer said there was an additional suggestion "that being in a wheelchair is also a reaction to your various mental health problems".

"You have paranoid, antisocial and borderline traits," the judge noted. "The point is that your mental health is not so serious that the mental health authorities can intervene without your consent, but you are, as a result of the personality disorders, assessed as a very high and continuing risk to the public."

Justice Brewer ordered a sentence in 2017 of two years - a length at which home detention is often considered as an alternative to prison. But he said he could not allow home detention due to the ongoing risk.

At Monday's district court hearing, Judge Winter set a sentencing date for April.

He faces one count of making a false allegation or report to police, which carries a maximum possible sentence of three months' imprisonment and a $2000 fine. He also pleaded guilty to breaching prison release conditions, which carries a maximum sentence of one year's imprisonment.

This story was originally published by the New Zealand Herald.