Peter Norris Dupas (born 6 July 1953) is an Australian convicted serial killer, currently serving three life sentences without parole for murder and primarily for being a serious habitual offender.

[4] On 3 October 1968, at the age of 15, Dupas visited his next-door neighbour, requesting to borrow a knife for the purpose of peeling vegetables.

[5] Less than two years after his release from prison, Dupas was arrested on charges of false imprisonment over an incident at Lake Eppalock in January 1994.

Wearing a hood and armed with a knife, insulation tape, and handcuffs, Dupas followed a woman who was picnicking and held her at knifepoint in a toilet block but was chased off by her friends.

Upon hearing music from a radio and discovering the front door unlocked, she entered the house and found the body of Patterson severely mutilated.

[4] Police investigations of the crime scene revealed Patterson had a 9am appointment with a new client by the name of "Malcolm" as noted in her personal diary alongside a mobile telephone number.

On 22 April 1999, police arrested Dupas at midday at the Excelsior Hotel in Thomastown and charged him with the murder of Patterson later the same day.

[4] A police search of Dupas's home revealed blood-stained clothing, PVC tape similar to that located at the crime scene, a ski mask, newspaper clippings detailing Patterson's murder, and also a paper containing her advertisement for psychotherapy services.

[10] Margaret Josephine Maher, 40, was a sex worker working in the Melbourne area who was last seen alive at the Safeway supermarket at 12:20 a.m. in Broadmeadows on 4 October 1997.

[7] Her body was discovered under a cardboard box containing computer parts at 1:45 p.m. on 4 October 1997 by a man who made the discovery while he was collecting aluminium with his wife and her sister beside Cliffords Road in Somerton.

[11] A black woollen glove was found near Maher's body which police later confirmed contained DNA matching that of Dupas.

[12] A post-mortem examination revealed Maher had suffered a stab wound to her left wrist, bruising to her neck, blunt force trauma with a cinder block to the area of her right eyebrow, and lacerations to her right arm.

During a trial lasting three weeks, evidence was presented to the jury that the removal of Patterson's and Maher's breasts were so "strikingly similar" as to be a signature or trademark stamp common to both crimes, thereby identifying Dupas as the killer of both women.

"It is clear, both in the present case and from your previous convictions for rape and like offences, that your offending is connected with a need by you to vindicate a perverted and sadistic hatred of women and a contempt for them and their right to live.

Even if there were, any considerations of rehabilitation must, in this case, be subordinated to the gravity of your offending, the need for the imposition of a just punishment, and the principle of general deterrence.

[11] Halvagis's murder had remained unsolved since 1997, with the Victorian state government, together with police offering an A$1 million reward for information leading to an arrest.

[15][16] Frank Cole, an elderly resident of Pascoe Vale, claims he saw Dupas leaving the Fawkner Cemetery on the day of the murder.

An anonymous female who was visiting her parents' grave on the day of the murder had also seen Dupas wearing sunglasses casually jogging throughout the cemetery.

'[22]After agreeing to give evidence against Dupas, Fraser was released from Fulham Correctional Centre in Sale on 11 September 2006,[8] two months short of his five-year sentence for drug trafficking.

[20] The Victorian government stated that Fraser was eligible to apply for a share of the $1 million reward offered for information leading to an arrest on Halvagis's murder.

[8] The Victorian Director of Public Prosecutions withdrew the charge of murder in the Melbourne Magistrates' Court and requested the case against Dupas be sent directly to trial, bypassing the committal hearing process.

[23] On 26 September 2006, Dupas appeared via video link in the Supreme Court of Victoria, charged with Halvagis's murder, entering a plea of not guilty.

[24] On 14 November 2006, Dupas appeared in the Supreme Court of Victoria before Justice John Coldrey, where he requested an opportunity to be able to cross-examine witness Andrew Fraser before a criminal trial takes place.

[25] On 12 December 2006, the Supreme Court of Victoria ordered Dupas be presented directly to trial for the murder of Halvagis, bypassing the usual committal hearing process.

On 10 September 2007, lawyers for Dupas submitted an appeal on the basis that the verdict of guilty for the murder of Halvagis was unsafe and unsatisfactory.

[35] On 14 October 2009, lawyers for Dupas argued that the proceedings against him should be stayed permanently based on the publicity surrounding the case.

[3] Dupas is a suspect in the murder of 31-year-old Brunton in the kitchen of her second-hand clothing store at a mall in Sunbury, Victoria on 5 November 1993.

[44] While imprisoned at Melbourne's Pentridge Prison, Dupas formed a relationship with mental health nurse Grace McConnell, who was 16 years his senior.

[3] McConnell described her marriage to Dupas during the inquest into the murder of Halvagis: "He insisted that he was in love with me .... and that with my help he could come out of himself and become a normal person.

[3][45] As of 2006, Dupas was serving his sentences between the maximum-security protection unit of Port Phillip Correctional Centre, at Laverton[21] and HM Prison Barwon in Lara, a northern suburb of Geelong.