Sammy Yatim shooting: 4 things you need to know

The trial for JamesForcillo, the Toronto police officer charged in the 2013 fatal shooting of 18-year-oldSammyYatimon a TTC streetcar begins todayin the Superior Court of Justice in Toronto.

Forcillopleaded not guilty to charges of second-degree murder and attempted murder in September.

Here's a primer of what you need to know as the trial begins:

AboutSammyYatim

Yatim, 18,was shot to death on July 27, 2013, after police responded to reports of a passengercarrying a weapon on a streetcar stopped onDundasStreet West nearBellwoodsAvenue in downtown Toronto.

Jurors will have to consider evidence from the Crown and the defence aroundwhat happened between the time officers arrived at the stopped streetcar and when Yatim was shot.

The teen was taken to St. Michael's Hospital, where he was pronounced dead that night.

About JamesForcillo

Less than four weeks after the shooting, following an investigation byOntario's Special Investigations Unit, Forcillo was charged.

The SIU,which investigates when police officers are involved in incidents where someone has been seriously injured, dies or alleges sexual assault,acted with what hadbeen noted as uncharacteristic speed in the shooting.

LawyerPeterBrauti,who is representingForcillo,regularly represents police officers in court.

What's at stake?

It's rare to see a Toronto police officer charged with second-degree murder. This is only the second time it has happened.Some legal experts have said it's also unusual that someone would be charged with second-degree murder and attempt to commit murder.

Second-degree murder involves a deliberate intent to kill but does not involve planning. It carries a sentence of life in prison with no parole for 10 years. However, parole ineligibility could extend for 25 years. Those decisions are at the judge's discretion.In this case, Justice Edward Then is presiding.

The second chargeis based on allegationsthat a firearm was used inan attempt to commit murder. If convicted of attempted murder, Forcillo would face a minimum sentence of fouryears since a gun was used.

What's happenedsince the shooting?

Besides the criminal proceedings,Yatim'sfamily issuingForcillo, the Toronto Police Service and the Toronto Police Services Board in a separate lawsuit for $7 million. The lawsuit alleged police acted with reckless disregard forYatim'slife.