AN argument over an untidy Warrnambool flat between new friends led to a frenzied stabbing attack in which the victim received 46 stab wounds.Callum Zane Smith, 20, who has a history of mental illness, yesterday pleaded guilty to stabbing and killing Christopher Leone outside the victim Koroit Street flat on June 14, 2006.Smith, of Port Phillip Prison, appeared in the Supreme Court, Warrnambool sitting, on the newly legislated charge of defensive homicide.Mr Leone was stabbed 46 times but received a total of 62 knife injuries.Crown prosecutor Mark Gibson said Mr Leone had lived at flat 3 No. 11 Koroit Street for about seven years when he was killed.He said Smith and Mr Leone had known each other two or three weeks and Smith had been going to the flat to listen to music, chat and smoke marijuana.On June 14, 2006, Mr Leone's mother Judy had taken her son to a pharmacy for medication he was taking as part of his drug rehabilitation. They went to lunch and Mrs Leone said her son was well and not agitated or mentally unsettled.The 31-year-old would be dead about two hours later.At 2.54pm the 000 emergency number received a call from Mr Leone's neighbour Jayden McIntyre who was concerned about yelling and fighting in the flat below him.Warrnambool police senior constables Reg Evans and Darren Pearce were on divisional van duties on Liebig Street and arrived at the Koroit Street flat about one minute after the call.When they arrived they saw Smith on top of Mr Leone outside the flat and he appeared to be thrusting punches to the victim.The policemen heard Mr Leone moaning and grunting and realised Smith was not punching but stabbing.Mr Leone received stab wounds to his neck, back, chest, abdomen, legs and arms.Senior Constable Pearce noticed a massive amount of blood and as he got closer Smith stopped stabbing, got up, dropped a knife and walked away from Mr Leone.As he walked towards police he said: ``I stabbed him in self-defence''.Smith was handcuffed and put in the divisional van while Senior Constable Evans tried to aid Mr Leone.The officer noticed a lot of blood coming from behind and below Mr Leone's right ear, which was where the internal carotid artery had been severed. After an ambulance was called and while Senior Constable Evans tried to stem the flow of blood the police tape-recorded Mr Leone's final words.The victim was taken to hospital but pronounced dead at 3.48pm.During police interviews Smith said he and Mr Leone argued about hepatitis C. He said that while visiting the flat Mr Leone had been ``not threatening me, but approaching to threaten me... talking about threatening me''.Smith claimed Mr Leone punched him once, looked at the knife, Smith thought Mr Leone was going to ``go him'' so he ran to the knife and started stabbing the victim.Smith said he kept stabbing because he thought Mr Leone was going to kill him.The court heard that Smith had been under the care of psychologist Simon Woodforth since July 2005 and admitted to a psychiatric ward in May and September 2005.He reported that Smith has a drug-induced psychosis. Mr Gibson said Mr Leone had posed little or no threat.He said Smith was the sole cause of Mr Leone's death.``It was a conscious, voluntary and deliberate act to intentionally kill or inflict serious injury,'' he said.Mr Gibson said the only other case of defensive homicide was less serious and resulted in a minimum term of 5 years in prison.He said Smith continued to take drugs despite receiving mental health treatment.Justice Elizabeth Curtain yesterday adjourned the plea hearing part-heard so an up-to-date report on Smith's mental health status could be prepared.Smith, who has already spent 695 days in custody, was remanded in Port Phillip Prison.