A 16-year-old who played a role in the killings of two Mac's convenience store clerks should not be convicted of first-degree murder, his defence lawyer says, because there is no evidence the teen caused the man's death.

The teen, who was 13 at the time, can only be identified by his initials G.S. He has already pleaded guilty to manslaughter in the death of another clerk killed at a different Mac's store on the same night. He pleaded not guilty to the first-degree murder of the second clerk, and that trial wrapped up with closing arguments Wednesday.

Defence lawyer Akram Attia conceded there was enough evidence to find G.S. guilty of manslaughter in the death of the second store clerk, Ricky Cenabre. But he argued the Crown did not prove beyond a reasonable doubt that the teen was guilty of first-degree murder.

"There was no evidence he physically caused the death of either person," Attia told Court of Queen's Bench Justice Donna Shelley. "Young people can't be held to the same standard."

The judge said this case was the first time in her career on the bench she has dealt with someone so young.

"How would you suggest I approach this, given his age?" Shelley asked Crown prosecutor Aleisha Bartier. "He's the only one without a weapon. It's clear he's not in charge."

Bartier argued the teen was a willing accomplice.

'Not spontaneous or impulsive'

"He's still aiding the two adults in the robbery," Bartier said. "He knows they're willing to use the firearm."

The teen, Bartier said in her written submissions, "had to have known that the second robbery would unfold in the same way. There was time enough between the two events for [him] to consider his actions and weigh the advantages and disadvantages of his continued participation.

"The second robbery was not spontaneous or impulsive."

But Attia argued the evidence in the case only provided proof of planning and deliberation to carry out the robberies, not the murders.

He said there was no evidence about any conversations that may have taken place between the first and second shootings.

The Youth Criminal Justice Act generally acknowledges that young people cannot be expected to anticipate the consequences of their actions in the same way adults can.

Attia noted that G.S. was 13 at the time of the killings and did not have the maturity to understand the consequences of his actions.

"He was crying and asking for his brother when he was arrested," Attia told the judge.

Two robberies, two killings

Early on the morning of Dec. 18, 2015, three masked robbers stormed into a Mac's store at 3208 82nd Street. One man was armed with a gun, the other had a machete. G.S. was carrying a duffel bag.

Surveillance video shows that during the robbery, store clerk Karanpal Banghu was repeatedly punched and struck with the gun. G.S. punched the clerk in the head while he was down on the floor.

Laylin Delorme then shot the clerk.​ Delorme was convicted in June on two counts of first-degree murder, and is scheduled to be sentenced in December.

At the time Delorme pulled the trigger, G.S. was seen on video hurrying toward the door, and the defence argued the teen may have heard the shooting but didn't see it.

Twelve minutes later, the trio walked into a second Mac's store at 10845 61st Ave. The two men carried the gun and a machete; G.S. went into the store empty-handed.

Surveillance video shows G.S. stood guard at the entrance to the till area while Cenabre was pistol-whipped by one man. But by the time Cenabre was shot in the back, the teen was already outside.

'They didn't deserve this'

The judge is expected to hand down her decision on the murder charge on Nov. 16.

Since G.S. has already pleaded guilty to five other charges, including manslaughter, the judge ordered a pre-sentence report. The court was told a psychological assessment has already been completed.

The other man charged in the case, Colton Steinhauer, faces a double first-degree murder trial scheduled for April 2019.

As the teen was led back to the cells on Wednesday, his mother stood in the courtroom and tearfully told her son she loved him.

"I'd like to say sorry to the family," she said, before family members led her away. "They didn't deserve this."