Tyson and Baker were both dealing synthetic drugs from the Jackson St flats and in the days leading up to the killing had been having a number of arguments around dealing, the summary of facts said.
Baker believed Tyson was an informant for HNZ, and after receiving his eviction notice he told Tyson he would be his "next victim".
On November 29, several unidentified Mongrel Mob members arrived at the flats and a fight was organised, involving one of the gang associates and Baker.
Baker received several kicks from his opponent before the gang members left the property.
"The defendant was visibly angry and in the aftermath of the assault could be heard yelling at the victim who was in the flat above," the summary said.
Baker yelled up to Tyson "I'm going to take your head".
His aggression increased the next day as he started moving his belongings out of the flat. Baker verbally abused Tyson and called him a "narc".
Later that day, he sent a series of text messages to an unidentified Mob associate telling them to let Tyson know "Eugene is still going to dehead your ass motherf***er hehehehehe".
About 20 minutes later he went outside and slashed Tyson's tyres.
When Tyson came home that evening with a large quantity of synthetic drugs, Baker armed himself with a large kitchen knife and went to his flat. He intimidated a boarder at the flat into letting him in, walked over to Tyson, and demanded he hand over all of his drugs.
Tyson refused and told Baker to leave or he would call the police, at which point Baker stabbed him five times in the chest, causing him to fall to the ground.
Baker punched through a hole in the bedroom door where the boarder had barricaded himself and coaxed him out into the living area, telling him to leave the flat otherwise he would witness the beheading.
"From his position on the lounge floor the victim managed to raise his head and plead for the boarder to leave," the summary said.
Baker escorted the boarder out and told him not to say anything about what he had seen, or he would be dead.
Tyson died on the floor of his apartment while Baker was out of the room.
When Baker came back, he used a large serrated bread knife to decapitate Tyson, wrapped the head in a towel, and placed it into a plastic bag he had brought with him.
He stole Tyson's cash and drugs before leaving the flat with the plastic bag and head and heading back to his own flat.
He tried to clean the blood off himself before he was interrupted by a screaming resident.
Several residents went to the flat and found Tyson's body on the floor. One woman began running through the complex raising the alarm.
Baker pulled her into his own flat to calm her down. He explained he had killed Tyson and would clean it up in a few days.
"The defendant loitered around the apartment block speaking with several more residents who were passing by. He made further admissions to killing the victim, stating that it was OK and he would have it cleaned up in a few days, and made reference to removing his head."
Later that evening Baker took the bag containing the head and "walked calmly down Jackson St swinging the bag, appearing to raise it towards the address of the known Mongrel Mob members who reside nearby".
He discarded the bag at an unknown address and returned home.
About 10pm police were called to the scene. On arrival they found Tyson's head had been returned to Baker, who had it stored in his lounge along with a large amount of synthetic drugs.
A search of Baker's person revealed 27 bags of synthetics.
Baker appeared in the High Court at Wellington this morning, where he pleaded guilty to murder.
Unrelated charges of intentional damage and possession of non-approved psychoactive substances for supply were withdrawn.
Justice Simon France convicted Baker and gave him a first strike warning.
He will be sentenced in June.
