Chilling CCTV images capture moment Kiwi was allegedly killed by Darwin gunman Ben Hoffman

Chilling CCTV images have caught the moment alleged Darwin shooter Ben Hoffman killed his last victim.

The grainy images allegedly show Hoffman shirtless and covered in blood as he walked from the home of New Zealand casino worker Rob Courtney, 52, who police say he murdered.

The shocking alleged murder came after police say Hoffman killed three other men with a pump-action 12-gauge shotgun on Tuesday while he was high on ice.

CCTV images show Hoffmann before the attack holding a shotgun. Photo / Supplied

After taxi driver Hassan Baydoun, 33, Nigel Hellings, 75, and Michael Sisois, 57, were shot dead, CCTV footage allegedly shows the 45-year-old Hoffman arriving at Mr Courtney's home in Woolner and walking inside, armed with a shotgun.

Courtney tried to defend himself and stabbed the gunman before he was allegedly shot dead in front of his housemate.

CCTV images then allegedly show Hoffman walking out, shirtless.

Mr Courtney was facing a charge of attempted sexual intercourse without consent and was due in court yesterday.

Hoffman, who is accused of the worst mass shooting in the Northern Territory's history will face a Darwin court today charged with murder.

Yesterday NT Police charged him with four counts of murder, two of recklessly endangering serious harm and one of criminal damage, with more charges expected over Tuesday night's deadly shootings.

Hoffmann will appear in court via video link from prison.

He is believed to have known two of the four men he is accused of shooting and killing in the bloody rampage.

Hoffman has had surgery for knife wounds since being tasered and arrested by police on Tuesday night. The surgery delayed detectives interviewing and charging him until Thursday.

The four killings occurred in about 30 minutes, with the gunman appearing to target specific locations.

Images capture the moment alleged shooter emerged from a victim's home covered in blood. Photo / Supplied

Police believe he was affected by the drug ice, which he has a history of using.

Police have not ruled out an accomplice being involved because the ammunition used with the shotgun was purchased by a "well-known associate" of Hoffmann's, Police Commissioner Reece Kershaw said.

When asked about the gunman's motives, he said there were potentially disputes relating to drug debts and a woman.

"There is a bit of both there. There is drugs, I think, I am speculating here, but we are following those two lines," Mr Kershaw said.

Police also revealed they had they pulled Hoffmann over for speeding just hours before the shooting.

Mr Kershaw said police had pulled the suspect over about 10.52am the day of the shooting at Arnhem Highway, Humpty Doo, for doing 94km/h in an 80km/h zone.

"He was not displaying any adverse behaviour," he said. "There nothing out of the ordinary (when he) was observed by police officers."

Mr Kershaw said he was "very satisfied with our approach" in letting the alleged gunman go.

He said it was a "possibility" the accused was seen with a firearm at the time, but that was still under investigation.

CCTV also shows Kiwi victim Rob Courtney before the attack. Photo / Supplied

"You have got to treat everyone fairly, and police officers have reasonable suspicions," he said. "They didn't have any at that point in time."

The alleged gunman was given an infringement notice for speeding.

The violence started at 5.39pm that day at the Palms Motel where Hoffmann allegedly shot and killed taxi driver Hassan Baydoun, 33, who was on a meal break.

Mr Baydoun's cousin Abdallah Salman said his relative did not know the shooter and was accidentally caught up in the shootings as the alleged gunman went from room to room firing his gun and shouting for a person named Alex.

A 23-year-old woman at the Palms who police do not believe knew Hoffmann was shot in the legs and remains in hospital.

The shooter went on to kill Nigel Hellings, 75, in Gardens Hill Crescent less than a kilometre away at what might have been the former home of an associate.

He then killed Michael Sisois, 57, who knew Hoffmann after previously working together, a few hundred metres away in the carpark of the Buff Club.

Taxi driver Hassan Baydoun.

He then drove two kilometres to Woolner where he tried to enter police headquarters, kicking the door before phoning Duty Superintendent Lee Morgan who negotiated with him and alerted police to his location.

The person named Alex, who Hoffmann was looking for in the days leading up to the killings, was interstate and was charged a fortnight ago in Darwin with various traffic and drug offences.

Ben Hoffman. Photo / Supplied

Vincent Sisois, the brother of Mr Sisois, angrily asked why Hoffmann had been released from prison on parole recently given he was known to be dangerous and violent.

"Why was he let out, they knew something would happen and they let him out. Why?" Mr Sisois said.

Accused Darwin gunman Ben Hoffman being led out of hospital into a police van. Photo / Supplied

The NT Government has asked for a report from the Parole Board on Hoffmann and to review all people on parole, however Attorney-General Natasha Fyles defended the system on Thursday.

Hoffmann is from a respected local family involved in business.