The inquiry will determine if the Crown has enough evidence to move forward with a second-degree murder charge against Forcillo, 30, who is accused in the death of Yatim last July.
The incident was recorded by security cameras and on amateur cellphone video. Nine shots can be heard on the videos, following shouts from police for Yatim to drop a knife he was reportedly holding during the confrontation.
The final six shots appear to come after Yatim had already fallen to the floor of the streetcar.
The inquiry is set to run until May 9.