The son of convicted murderer Gordon Cramp revealed to The Daily Telegraph it was an addiction to ice that turned his father into a killer.

“My dad’s not a violent person, never has been,” Gordon Cramp Jnr said.

“He was a very respectful man, worked every day. He did have his times where he slipped up, as any man would.”

Ice-induced violence has become a major problem facing Australians over the past decade. Some of the most horrific murders and assaults have been linked to the drug and there is a common theme of uncontrolled rage combining with superhuman strength. On Sunday Prime Minister Malcolm Turnbull announced a $300 million plan to address the scourge with focus on prevention in combating the problem.

After the graphic details of Cramp’s violent attack were played out in a courtroom earlier this year, Supreme Court Justice Michael Adams sentenced the 40-year-old to 40 years in prison, calling him a “dangerous individual” who required a sentence that recognised “the need for the protection of the community”.

A VIOLENT UNPROVOKED ATTACK

In the early hours of February 21, 2013, Lance Hargreaves was brutally murdered at the Solveco waste recycling plant he worked at in the outer Sydney suburb of St Marys.

That morning Cramp had injected ice and smoked marijuana at a friend’s house.

He had been fired from the plant just three months earlier but convinced a friend to drive him there to score more drugs from a former colleague.

Carrying only a bag that contained two knives — one described in court as an ‘army-style’ knife and the other a ‘US military-style’ blade — Cramp entered the plant and spoke to a number of former workmates before heading into the lunchroom where he encountered Hargreaves

The 62-year-old was on a break having worked the night shift when Cramp demanded he call the worker he was attempting to buy drugs from.

Cramp became increasingly frustrated at the older man’s refusal. Over the next few minutes, Cramp stalked him through the plant, climbing on to a truck and cutting the wires to a CCTV camera. In total, four cameras were disabled.

The pair was seen arguing by witnesses before they disappeared behind a stack of crates where Cramp removed a knife from his bag and stabbed Mr Hargreaves in the neck.

The attack was so savage it completely severed Mr Hargreaves’ spinal cord.

The wound, measuring 12cm long, cut through the space between the second and third vertebrae.

Cramp went on the run after the brutal killing, with his mother Carol even making an impassioned please for her son to turn himself in. On March 2, nearly two weeks after the attack, Cramp walked in Windsor Police Station and was arrested.

During his murder trial, Justice Adams found Cramp didn’t go to the waste recycling plant with the intention of killing Mr Hargreaves, but when he removed the knife from his bag inside, it was with the intention to kill.

TURNED TO DRUGS AT A YOUNG AGE

Cramp grew up in Western Sydney, the eldest of two children.

He had a close bond with his father until his death when Cramp was just 15-years-old.

This had a profound impact on the teenager who turned to illicit drugs to cope with his grief.

That same year he left school and worked a number of different jobs to make ends meet.

Then in 1990 he started taking amphetamines and became addicted.

‘ICE CHANGED MY DAD’

Cramp’s son said his father had been a “respectable” and “hardworking” man before he started using ice after a bad breakup.

He said his father, who he referred to as his “best friend”, didn’t have a violent past although he did have multiple convictions for assault dating back at least 11 years before Mr Hargreaves’ death.

Mr Cramp Jnr was 20 and in jail himself when his dad was arrested for murder.

He said he knew exactly what ice did to a person as he had struggled with addiction in the past.

“I know the drug too — I slipped up a little bit — and it’s not a nice drug,” he said.

“The person you are, in all your morals and the way you think, you’re the complete opposite.

“It’s a mind addiction. You need it to get up, you need it to feel good.”

He said his time behind bars was a blessing as it helped him kick the habit and get his life on track.

“Going to jail was the best thing to happen to me, to get off that drug,” he said.

“I’ve turned my life around and I’ve got a daughter on the way now. I’m on a good path.”

Mr Cramp Jnr is in regular contact with his dad.

He said his father denies he killed Mr Hargreaves and said he was shocked when the jury came back with a guilty verdict for murder, instead of manslaughter.

“Let’s say he allegedly went there to do something wrong — but not what happened — that is not a murder, that is a heated thing gone wrong. Manslaughter,” Mr Cramp Jnr said.

ICE KILLERS: AN INSIDE LOOK

CHAPTER 1: HIGH ON ICE WHEN HE STABBED A FORMER COLLEAGUE TO DEATH

CHAPTER 2: ‘HAVE A F***ING LOOK AT THAT’, ADDICT YELLED AS HE STABBED VICTIM MORE THAN 100 TIMES

CHAPTER 3: HE BASHED HIS TEEN GIRLFRIEND SO VIOLENTLY SHE LOOKED LIKE A CAR CRASH VICTIM

CHAPTER 4: HOW THE TOXIC DRUG EFFECTS THE BRAIN TO FUEL RAGE AND VIOLENCE

CHAPTER 5: HELPING ADDICTS THE CURE TO OUR ICE HABIT

A HISTORY OF VIOLENCE

While Justice Adams found that Cramp was in charge of his actions — denying the accused’s assertion he was ‘not thinking clearly’ because of the drugs — he may have been high on the same drug in a ‘troubling’ serious assault more than a decade earlier.

It’s believed Cramp may also have been high on the drug when carrying out another “troubling” serious assault more than a decade earlier.

In 2002, Cramp, who had recently split from his de facto, was driving when he spotted a relative of his former partner who had been offering the woman emotional support during their split.

Turning his car around he chased down the man and stabbed him in the back a number of times while yelling “I’m going to kill you”.

The victim suffered serious injuries and Cramp was sentenced to seven years’ jail for the attack.

He was also found guilty of a number of other assaults and was on bail when he killed Mr Hargreaves.

Cramp has appealed his conviction and sentence but a date for the case to be heard in the Court of Criminal Appeal has yet to be set.