Moore faces four counts of first-degree murder to which he has pleaded not guilty.
On Monday, Crown attorney Sean Hickey told the jury that all four of the killings that Moore is accused of can be independently linked to him and no one else.
Hickey said the same semi-automatic, 9-mm Smith & Wesson handgun was used in all four shootings.
Jahmeel Spence was shot dead in September 2010 near his mother-in-law's house.
Later that month, Mike James and Courthney Facey died in a drive-by shooting, slain by bullets fired from the same gun.
In November of that year, Carl Cole was shot to death with that same handgun.
The Crown has never been able to physically tie the gun to Moore.
But Hickey said "there is no serious evidence that the time covered by the indictment, that the gun moved from hand to hand. It remained Mr. Moore's gun."
The Crown reminded the jury that Moore tried to sell a 9-mm handgun after being released on bail for drug charges.
Hickey told the jury "it was a wake-up call to Mr. Moore ... a realization that he had to get rid of the dirty guns... because he knows it's going to link him to the homicides."
The gun used in the homicides was seized by police some 13 months after Cole's death.
Hickey said that if the jury members found beyond a reasonable doubt that Moore was in possession of the gun when the first and fourth men were killed, it stands to reason he had it when the two other men died in the drive-by.
The Crown is expected to wrap up its closing arguments on Tuesday, while the defence is expected to provide a different interpretation of the evidence on Wednesday.
Watch the video to see a full report from the CBC's Michelle Cheung.