Moments after the bloody murder of his dominatrix's boyfriend, Stuart Heron pushed past a neighbour and waited for the lift.
"Guys it's him - go," the neighbour screamed at police, who had just arrived at the apartment building.
Heron was arrested while standing in front of the lift, with a large knife covered in blood on the ground beside him.
He was carrying a bloody hammer, silver handcuffs and a dog's leash.
Other neighbours rushed out to the car park, where they found 39-year-old Nick Cameron bleeding to death on the ground.
Heron had promised his dominatrix, Heide Bos, she would never have to see her boyfriend, Mr Cameron, again.
They had met on a fetish website six weeks earlier, where Bos went by the name "Hedonistic Siren" and said she wanted to meet "slaves".
Heron's profile said: "I pride myself on my service, which includes being her personal play toy, cook, cleaner, masseuse, handyman, builder, mechanic, amongst other things."
He became her slave and when she told him she was having issues with Mr Cameron, Heron was willing to assist.
"Seriously Heide, if you need anything at all ... just let me know," he told Bos.
Bos asked Heron to physically confront her boyfriend so he would leave town and not come back.
"As her slave, Ms Bos' unhappiness was Mr Heron's unhappiness," prosecutor Elizabeth Ruddle SC told the Supreme Court.
He staked out Mr Cameron's Melbourne apartment in the days before the killing, at one point spending seven hours in and around the building.
After an argument with Mr Cameron, on July 9, 2021, Bos gave Heron the go-ahead to confront him.
"I'm 99 per cent certain I can convince him to never contact you again, my lady," Heron told Bos.
Bos gave Heron details of where Mr Cameron's red hire car was parked.
She then lured her boyfriend out of his apartment by telling him someone they knew "wanted to catch up and pay him back money".
Just before midnight, Mr Cameron left his home with his dog Misty and walked to the garage, where Heron was laying in wait for him.
Using a hammer and knife, Heron murdered Mr Cameron over 11 minutes.
Mr Cameron suffered more than a dozen blunt force head injuries in the attack and two stab wounds.
Paramedics pronounced him as dead at 12.45am on July 10.
Heron, 50, who has pleaded guilty to murder, faced a pre-sentence hearing on Monday where Justice Michael Croucher labelled his plan as "harebrained" and "strange".
"He seems to have been infatuated with Ms Bos, he's lonely, his other relationship ended, he was hopeful of something more with her," the judge said.
"He's in this strange fantasy world of a subservient relationship and for whatever reason, he agrees to this harebrain scheme to confront this man and assault him."
Heron's barrister Richard Backwell said his client told a psychologist the killing was "the worst decision he's made in his life".
He said Heron did not intend to murder Mr Cameron.
"He was there at the behest of Ms Bos … he acted upon the things that she told him," he said.
Heron will be sentenced on September 8.
Bos was jailed for up to six years and three months in February after admitting manslaughter over her complicity in arranging the attack.
