MONTREAL -- The jury at the trial of a Nova Scotia man charged with two counts of first-degree murder in a 2010 Montreal double slaying heard more testimony on Tuesday from another man who actually pulled the trigger.

Leslie Greenwood, 45, is accused of being the getaway driver in murders which another Nova Scotia native, Robert Simpson, has admitted to committing.

Simpson, 53, is serving a life sentence for gunning down Kirk (Cowboy) Murray and Antonio Onesi in a McDonald's parking lot in Montreal in January 2010.

Now a co-operating Crown witness, Simpson continued his expletive-peppered testimony as he outlined how he and Greenwood were sent to Montreal to kill Murray at the behest of Jeffrey Albert Lynds, a former full-patch Nomad from the Hells Angels Ontario chapter who lived in Nova Scotia.

The witness said Greenwood knew their trip was to "take out Cowboy" and that he was supposed to "get Bobby back in one piece," he said, referring to himself. Simpson said he brought his brother Timothy as backup.

Simpson said they had a 30-minute conversation at a "fleabag motel" near the scene, brainstorming on how to pull off the hit.

He alleged Greenwood suggested the murder be committed at the motel and be followed by dismemberment and setting the room on fire.

The double murder, the jury has heard, was part of a complicated settling of accounts. Murray was killed in part because of a botched hit involving another Montreal drug trafficker.

"That's a big, big no-no, you're not supposed to miss," said Simpson, who on Monday admitted to being the author of several murders himself.

Lynds had also promised Murray a place in the Hells, a pledge he couldn't keep since he too was no longer in good standing with the criminal organization after a fallout with a trafficker.

Murray was lured to the scene under the guise of being paid $9,000 in drug money, but Simpson said he put 14 bullets in Murray and Onesi before hopping into a car driven by Greenwood and returning East.

Simpson testified that upon returning to Nova Scotia, he considered killing Greenwood, but Lynds convinced him to let it drop.

"He's a loose link to me and to the crime," Simpson told the jury. "It was one less person to link me to that crime."

Simpson said he agreed to kill Murray and Onesi for $40,000, but relations began to sour with Lynds when no money materialized.

Simpson said he met Lynds in 2009 after unlawfully fleeing a halfway house and was hired as a bodyguard.

In his line of work, Simpson said he was always suspicious.

"It's a pretty double-cross world and I was always worried I was going to do a contract and I was the contract," Simpson said.

The killer told the jury he returned to Montreal not long after the double killing in a search of money and killed another drug dealer named Mark Stewart as part of a robbery, with his brother disposing of the body in the bushes.

Simpson recounted that he and Lynds ended up having a burger at the very same fast-food restaurant where the first double slaying took place.

Simpson and Lynds were arrested in Truro, N.S., on Feb. 12, 2010.

He told the court on the day of his arrest that he had decided to kill Lynds and was armed, waiting for the opportune moment.

The trial is expected to continues for several more weeks.