A love-sick man who terrorised Darwin during a drug-fuelled shooting spree has admitted gunning down four people, cutting short a seven-week trial.
Benjamin Glenn Hoffmann had pleaded not guilty to committing four murders in less than an hour at four locations on June 4, 2019.
He'd also denied 10 other serious charges, including threatening to kill and recklessly endangering life.
But on Tuesday, the 47-year-old entered guilty pleas to eight of those offences, including murdering, Hassan Baydoun, 33, Michael Sisois, 57, and Rob Courtney, 52.
He also pleaded guilty to the manslaughter of Nigel Hellings, 75, after the prosecution agreed to accept the lesser charge.
The Crown accepted the guilty pleas "in full satisfaction" of the 14-count indictment.
It immediately ended the Northern Territory Supreme Court trial and Justice John Burns dismissed the jury.
Lawyers wasted no time moving to sentencing submissions with Hoffmann's mental health at the time of the attacks expected to be a key component to determining his jail time.
Forensic psychiatrist David Greenberg told the court Hoffmann wasn't suffering from a mental illness when he pulled the trigger.
"He was actively seeking out and pursuing his enemies or who he perceived were his enemies," he said.
The Crown had alleged that Hoffmann was hunting for the Alex Deligiannis, the man his ex-girlfriend, Kelly Collins, said she loved.
"He felt he was some sort of saviour or protector of Kelly," Professor Greenberg said.
"He was purposeful and methodical, and some of the witnesses said he was calm and controlled."
Hoffmann also made plans and was acting on thoughts he'd had before the killings, Prof Greenberg said.
He also showed insight and judgment during the rampage and did not kill all the people he came across.
Prof Greenberg described Hoffmann as paranoid, impulsive and remorseless, and said he had a history of violence.
He said he also suffered from a personality disorder and a substance abuse disorder.
Hoffmann was high on methamphetamine when he killed the men, which Prof Greenberg said would have emboldened and disinhibited him.
The court heard Hoffmann had also malingered and exaggerated his claims about the mental health symptoms he suffered before and after he shot dead the four men.
"He tended to use catchphrases that were professional technical terms ... but he didn't really understand these terms," Prof Greenberg said.
Hoffmann shot Mr Baydoun four times with a double-barrel shotgun at the Palms Motel in central Darwin.
Mr Hellings was gunned down through the front door of his apartment block about 800m away.
Hoffmann's next victim was his mate, Mr Sisois. He was shot in the head in the car park at the nearby Buff Club bar and restaurant.
Mr Courtney died at an industrial yard at Darwin Recycling, about 2.5km away.
He was found with 69 injuries, including 36 stabbing and slicing wounds, multiple blunt force injuries and a gunshot wound.
Mr Deligiannis had previously visited three of the locations regularly.
Hoffmann and Ms Collins met in early 2019 in a drug rehab centre, where the pair made plans to move in together after they left the program
But two weeks before the shootings, Ms Collins sent Hoffmann a text message saying she was in love with Mr Deligiannis.
In the days after the text, Hoffmann repeatedly told workmates he was going to "blow (Alex's) head off".
Sentencing submissions continue on Wednesday.
Australian Associated Press