Ahmed Jaghbir, 31, pleaded not guilty to being an accessory before the fact over the shooting murder of Kemel "Blackie" Barakat in his western Sydney home in 2017.

But Justice David Davies found Jaghbir guilty of helping the four assassins get into the Mortlake unit block on March 10, after he was called to help fix a damaged door and lock.

The court had been told Mr Barakat's slaughter was in the broad context of a series of numerous retribution-style murders including Hamad Assad, a friend of Jaghbir.

The judge said Jaghbir had three possible motives, including suspicion over Mr Barakat's possible involvement in Mr Assad's death and apparently Mr Barakat's "crew" ripping $265,000 off Jaghbir.

Justice Davies agreed with Jaghbir's defence lawyer Gregory James QC that the key was not essential for the murder to be committed.

But it enabled the killers to enter the unit expeditiously without warning to Mr Barakat, "and without perhaps alerting neighbours by breaking down the door", Justice Davies told the NSW Supreme Court on Wednesday.

As Barakat slept with his partner Fatima Hage the disguised assailants shot Mr Barakat multiple times in bed before fleeing, having been inside the complex for less than four minutes.

The burnt-out getaway stolen Mercedes was later found with handles that had been removed from the Mortlake apartment security door two days before the murder.

As the killers silently made their way to Mr Barakat's bedroom door, he was not given the possibility to flee over the balcony or shoot the intruders first, making Jaghbir's role "a significant one".

So concerned for his safety was Mr Barakat he had asked for Jaghbir's help to replace the door which police had previously smashed down.

Jaghbir then provided the group of assailants information about a fire staircase at the back of the apartment block, from which they entered, and gave a key to Mr Barakat that was later found to be duplicated.

This "special relationship existing between them ... amounted to a position of trust.

"This was no different to a tradesman taking advantage by spending time in someone's home then conveying knowledge about the layout and where valuable items were kept to a prospective burglar," Justice Davies said.

He accepted there was not a lot of planning from Jaghbir, and that his role in the crime came about "fortuitously".

Jaghbir was sentenced to a maximum prison term of 11 years and will first be eligible for parole on April 9, 2027.

He is already serving a separate sentence of one-year for perverting the course of justice after helping his controversial business associate Salim Mejaher stage a car crash to get out of a court appearance.

Australian Associated Press