The decision to follow a stranger home and drive a knife into him more than 20 times was the work of a “very disturbed mind”.

That’s how a judge described Daniel Jack Kelsall’s action in stabbing to death Sydney businessman Morgan Huxley on September 8, 2013.

The 22-year-old former kitchen hand stared straight ahead as he was told on Wednesday that he will spend at least 30 years in prison for Mr Huxley’s murder.

• ‘Worthless psychopath’ guilty of murder
• Not guilty plea in Huxley case
• Indonesia executes Bali Nine duo

Describing it as a “chilling case of murder”, Justice Robert Allan Hulme added, “whether the offender killed for the thrill of it … or whether it was as a result of fantasy or obsession I am unable to say. It was entirely senseless and needless”.

“It must have been the doing of a very disturbed mind.”

The irrational purpose of such an act could only be known by Kelsall, he said.

Like his demeanour throughout his two-week trial in March, Kelsall made no reaction as the judge described the events leading up to the brutal attack.

In the year before the murder Kelsall had confessed to having thoughts of killing a “total random” with a knife, the Supreme Court heard.

Justice Hulme could not be satisfied Kelsall formed an intention to kill Mr Huxley when he spotted him at the Oaks Hotel in Neutral Bay.

Family say Morgan Huxley had everything to live for and his life was taken by a monster. Photo: AAP

However, he found the 22-year-old did track his victim from the pub and watch him enter his nearby unit.

When he realised the door was left open – as was Mr Huxley’s habit – Kelsall went inside and attacked the 31-year-old as he lay either asleep or incapacitated by alcohol.

He indecently assaulted him before plunging a knife into him more than 20 times.

Kelsall’s intelligence fell within the “superior range” – meaning his functioning was at a level equal to or better than 95 per cent of the normal population.

In a psychological assessment prepared for the court this month, Dr Susan Pulman reported that when Kelsall was asked to provide a meaning for the word “terminate”, he responded immediately “to kill”.

When this was queried – as other individuals typically say “to end”, “to finish” or “to stop” – Kelsall replied it meant “to completely extinguish the life source”.

“Whilst he demonstrates an understanding of empathy from a cognitive perspective, he appears to have limited emotional resonance or connection with other’s emotional experiences,” Dr Pulman noted.

“Detached and composed in his behaviours”, she said it was consistent with a personality disorder characterised by psychopathic traits.

Justice Hulme also found Kelsall had shown no remorse and that his version of events at trial – that Mr Huxley had invited him in and they had been attacked by an intruder or intruders – was fanciful.

The total maximum sentence is 40 years and three months, with Kelsall eligible for parole in January 2044.

Speaking outside court, Kelsall’s father Mark said he was sorry for the Huxley family who also were at the sentencing.

– AAP