Debs, from Narre Warren, a south eastern suburb of Melbourne was employed as a tiler. He had fathered five children. His youngest son Joseph was found dead due to a suspected drug overdose at a house in Greensborough in December, 2003.
In February, 2003, Debs was convicted and sentenced to two consecutive terms of life imprisonment with no minimum term for the murders of two Victoria Police officers, Sergeant Gary Silk and Senior Constable Rodney Miller at Moorabbin, Victoria on 16 August 1998.
Accomplice Jason Joseph Roberts, who was 22 at the time of sentencing, was also convicted of the police murders and sentenced to two consecutive terms of life imprisonment with a minimum term of 35 years.
On 20 June 2005, police charged Debs with the murder of troubled teenager Kristy Mary Harty, who was murdered at Upper Beaconsfield on 17 June 1997.
Harty was soliciting for sex along the Princes Highway when she met with Debs. The pair drove to a secluded bush track in Upper Beaconsfield where they had unprotected sex. Harty was later murdered. Her semi-naked body was found lying face down by bushwalkers. A single gunshot wound was discovered at the rear of her head.
DNA tests revealed semen located on the body of Harty that was linked to Debs.
In May 2007, Debs was convicted of the murder of Harty and sentenced to a third consecutive term of life imprisonment.
In sentencing Debs, Justice Kaye remarked:
Your murder of Ms Harty was entirely senseless, needless and wanton. The evidence discloses beyond any doubt that this was not a case of a sexual encounter in which, in the heat of the moment, feelings or passions may have led to a spontaneous and irrational act of violence. Rather, and quite to the contrary, this was, most clearly, a callous, craven and senseless murder in cold blood of an entirely innocent, defenceless and vulnerable young woman. The evidence leads to the inevitable conclusion that you murdered Kristy Harty for no other reason than for the sheer sake of it.
Donna Anne Hicks was shot dead in April 1995 in western Sydney.
Debs was subsequently linked to the case through DNA analysis. Debs had been entered into a DNA database of criminals. On 30 September 2008, Melbourne detectives interviewed Debs and raided his previous address in Sydney. On 12 December 2011 he was found guilty of Hicks' murder in the New South Wales Supreme Court. He was sentenced to a fourth consecutive life term for the murder.
While imprisoned, Debs has undertaken psychology, life skills and computer training and is employed as a prison carpet cleaner.