The Daily Telegraph can now reveal that the man was one of two who came forward after hearing of Huxley’s death to report their brush with the depraved killer just streets away from where the young businessman was stabbed to death.

Chillingly, six months before his murder, Mr Huxley also told friends a man followed him home and forced his way into his Neutral Bay unit where he was later stabbed 28 times.

Detectives have no way of knowing whether the man was Kelsall, but are confident he was involved in at least two other incidents in the same area.

One of the men came forward to tell police he was having a cigarette outside a block of units in Spruson St when a man, later identified as Kelsall jumped out from behind a bush.

At the time just two months before the murder, Kelsall was living in the same street with his adopted parents.

Then more disturbingly just a week after the murder as police were hunting for the killer - Kelsall, dressed in his chef’s uniform, followed a second man along Ben Boyd Road almost to his front door.

The young man confronted Kelsall who then ran off. Both men contacted police about their encounters with Kelsall after publicity surrounding the case.

The incidents and savagery of the murder prompted police to carry out checks into Kelsall’s past in New Zealand, cross-checking any unsolved murders around the time he lived there.

Detectives made inquiries with counterparts in his home town of Khandalla, 15 mins from Wellington, which The Daily Telegraph visited and discovered Kelsall’s acquaintances remembered a loner with a penetrating stare.

Police were given yet another troubling insight into Kelsall’s twisted mind after seizing his computer. They discovered a sick history of internet searches for ghoulish autopsy images, “DNA” and animated child porn, which he is still due to face charges for in April.

The young kitchen hand was yesterday found guilty of murdering Mr Huxley in a frenzied knife attack after following him home from the Oaks Hotel in Neutral Bay on September 8, 2013.

Police first spoke to Kelsall after a local shop owner identified him in CCTV footage running to catch up to Mr Huxley as he left the hotel and started his 100m journey home.

At first he lied about knowing Mr Huxley or knowing anything about the murder. But incredibly, he later called detectives to put himself front and centre in the case, telling them he had not told the whole truth.

After first claiming to have no involvement, Kelsall backtracked and told detectives he had in fact walked home with Mr Huxley and was invited inside his unit for a consensual sexual encounter.

And he changed his story again at trial, making the explosive claim that he and Mr Huxley were assaulted by an unknown intruder.

Kelsall’s lies compounded his guilt, with DNA evidence, Mr Huxley’s blood on his chef’s bag and CCTV footage sealing his fate.

But the most damning piece of evidence for many was Kelsall’s admission to a psychiatrist that wanted to murder a random person with a knife for “the thrill of it” just 16 months prior.

Kelsall said he “got rid of evidence” that may have linked him to the murder because he was “scared and wanted to disassociated myself”. But jury saw through the lies.

This was not a crime of passion or jealousy. The “awful truth” was that Kelsall killed for the sake of killing, the court heard. An unprovoked, senseless, motiveless murder.

That’s what made the crime so evil, senior detectives say.

“What a tangled web we weave when first we practice to deceive,” the Crown prosecutor said in his closing address on Tuesday, quoting author Sir Walter Scott.

While he would not speak about Kelsall specifically, forensic psychiatrist Julian Parmegiani said those who killed for the “thrill” often did not stop at one, adding weight to the theory that Kelsall would have killed again and again.

“The people who carry out these kind of acts know exactly what they’re doing, they know it’s morally wrong, legally wrong. But they enjoy it so much that they don’t care about anyone else,” Dr Parmegiani said.

“It’s generally not going to stop. Because it follows a long pattern of rehearsing, getting excited about the kill. Once the crime is over, the feeling of absolute power dissipates over time so the internal fantasies start again.

“It takes a particularly callous person to carry out a thrill kill – someone who lacks remorse and doesn’t care about the victim’s feelings of the feelings of the relatives.”