MONTREAL—A slew of new charges tabled on Friday showed a dangerous wild streak in the days before a 12-year-old Dorval boy was arrested to face a manslaughter charge in the shooting death of his older brother.

According to crown prosecutor Marie-Claude Bourassa, the 12-year-old is suspected of taking part in a hold-up in the days before his teenaged brother was killed.

While his identity is protected, the suspect will now face additional charges of armed robbery, possession of a prohibited weapon, possession of a firearm in a vehicle, conspiracy and taking a vehicle without the owner's consent.

Charged along with the 12-year-old is another minor. The prosecution alleges the two conspired to commit the robbery and then carried it out using a loaded gun. The crown says the new charges are not related to the shooting death that followed.

“The investigation happened completely separately but lead to the arrests of two youths,” said Bourassa.

Days after the hold-up, police were called to the boy's Dorval home, where on Jan. 21 they found a 16-year-old boy dead from a gunshot wound to the head.

The following day, the 12-year-old was arraigned on a charge of manslaughter and being in possession of a prohibited weapon.

The 12-year-old was supposed to be in court on Friday for bail arguments, something the crown vehemently opposes in both the shooting and alleged robbery.

“Based alone, on the use of a charged prohibited, weapon to commit such a crime as robbery, we would object to the release,” said Bourassa.

The question of bail on the new charges will be dealt with at the same time as the older charge of manslaughter. The teenager will be back in court Feb. 27 for a pro forma hearing, likely just to set another date for a bail hearing.