Nick Chan — the accused leader of one of Calgary's most notorious and deadly gangs — has been found not guilty in the death of Sanjeev Mann at the Bolsa Restaurant in Calgary in 2009.

Chan was a key figure arrested during the Calgary Police Service's largest gang investigation ever, which was dubbed Operation Desino.

The jury rendered the verdict Tuesday morning after about five hours of total deliberation that began late Monday afternoon.

Desino involved granting several confessed killers immunity or partial immunity in exchange for their testimony against Chan.

The Crown's star witness, who can only be identified as GH, was a recipient of one of the deals. He admitted to killing rival gangsters and will be eligible for parole in May.

Adam May Crown prosecutor

Prosecutor Adam May says the Crown put its "best case forward" in front of the jury. (Meghan Grant/CBC)

The case was heavily weighted on his testimony, which Chan's lawyer was highly critical of throughout the trial and in his closing arguments to the jury.

GH was the only witness to implicate Chan as the one who instructed the killing of Mann, who was the intended target in the triple murder at the Bolsa Restaurant on Jan. 1, 2009.

The Crown said during the trial that the attack had been orchestrated by Chan, a leader of the Fresh Off the Boat (FOB) gang, as part of a brutal war with the gang's fierce rivals, the FOB Killers (FK). 

The gang war between FOB and FK left 25 people dead between 2002 and 2009.

'We respect the verdict'

"We put the best case forward that we could in front of the jury," Crown prosecutor Adam May said after the verdict was issued.

"They didn't agree with our framing of the evidence, but we respect the verdict."

May said Calgary police "did an amazing investigation" and he didn't think there was anything more investigators or the Crown could have done.

CBC News contacted Calgary police for a comment but received a written statement.

"The Calgary Police Service respects the decision of the jury in the case of Nicholas Chan. As Mr. Chan is currently before the courts on other matters, the CPS is unable to comment further on this issue."

Two other gangsters have already pleaded guilty to killing the other two people who died in the shooting: Mann's associate Aaron Bendle and Keni Su'a, an innocent bystander.

si-mann-bendle-sua

Sanjeev Mann, 22, Aaron Bendle, 21, and Keni Su'a, 43, were shot and killed in a revenge gang plot January 1, 2009. (CBC)

Defence attorney Dick Cairns said he believes justice was done.

"I believe in the jury system," Cairns said. "I don't believe anybody should be convicted of anything on the evidence of people like [GH], who's a multiple murderer."

Chan remains in custody and still faces charges of murder, conspiracy to commit murder and instructing a criminal organization in relation to the death of Kevin Anaya in another gang-related killing.

Chan's trial in that matter is set for October 2017.