A man has been jailed for 35 years after murdering a teenager so they couldn't "snitch".
Yigit Can Erdogan, 23, was found guilty by a jury in May last year of murdering the 17-year-old male in March 2019.
Two others have been sentenced over the crime, which Erdogan was accused of orchestrating after a dispute over claimed stolen property.
Justice Mark Ierace described Erdogan as the "dominant personality" in the murder and sentenced him to 35 years with a 24-year-non-parole period in the NSW Supreme Court on Friday.
The judge described the murder as "reprehensible in the extreme".
It was premeditated, prolonged, callous and entirely unprovoked, also featuring aspects of "gratuitous cruelty", the judge said.
The teenager, who was detained for hours, was beaten, stabbed and had his head stomped on at a home in Sydney's west.
His body was found in a shallow grave in the Blue Mountains, wrapped in plastic and tape, eight days after he was last seen by his family.
He was naked except for his underwear, with at least 22 stab wounds to his neck, a fractured skull and brain bleeding.
"This kid is so injured that if we take him to the hospital he is going to snitch. We need to kill him," a witness during the five-week trial described Erdogan telling them.
Another witness recalled similar concerns from Erdogan that the teen would "snitch", while a third recalled Erdogan saying the teenager had to die because "he was going to rat".
"His motive for the offence was to avoid being charged by police in relation to the assaults," Justice Ierace said.
He did not consider Erdogan to be a reliable witness and took a cautious approach to his evidence.
Erdogan said he told others he did not want to be involved while the teenager was being assaulted and went to sleep on the couch, waking in the late afternoon to find the teenager was dead.
"Clearly this account was rejected by the jury," the judge said.
Justice Ierace found Erdogan had instead instructed others to "soundproof" the house by closing windows and blinds and playing "loud, deep bass electronic music".
"Because he intended to inflict really serious bodily harm," Justice Ierace said.
He was also satisfied beyond reasonable doubt Erdogan, and no one else, was responsible for stabbing the teenager in the neck with two knives, snapping the blade from one.
The judge said Erdogan had not shown remorse.
He had denied responsibility and had mocked and belittled the victim after his death to two other people, performing an impression of the teenager gurgling blood as he died in one instance.
He was on bail at the time he murdered the teen and the judge held "guarded" prospects of his rehabilitation.
Erdogan was born in Turkey, moving to Australia from Germany when he was 10.
The judge took into account his age, 19 at the time of the offence, and said long-standing mental health issues had destabilised Erdogan's ability to function in society.
Justice Ierace said he also took into consideration the brutality of the murder, which was unprovoked, and which Erdogan had involved others in.
He will be eligible for parole in April 2043.
