TORONTO - A jury weighing the case of a Toronto police officer charged with murder after gunning down a teen on an empty streetcar is into its second day of deliberations.

Const. James Forcillo has pleaded not guilty to second-degree murder and attempted murder in the death of 18-year-old Sammy Yatim.

The July 2013 incident was captured on cellphone videos which went viral online, sparking anti-police protests in the city and a review of Toronto police tactics.

The jury determining 32-year-old Forcillo's fate has to decide whether he ignored other viable use-of-force options and acted as "a hothead and a bully" when he shot Yatim, or whether he pulled the trigger in self-defence.

The judge presiding over the case issued a series of clarifications to the jury on Thursday morning after both crown and defence lawyers raised objections to portions of his instructions to the panel.

During the trial, crown prosecutors argued Forcillo's actions weren't necessary or reasonable, while his lawyer called those actions justified and carried out in self-defence.