The shooting, which was captured in amateur video posted online, has Yatim's family demanding answers.
They've seen the video, which includes the sound of nine gunshots. When the audio is enhanced, a stun gun can also be heard after the shots are fired.
Yatim's younger sister, Sarah, has created a Facebook group called "Sammy's Fight Back for Justice."
The group, which had more than 5,000 likes as of 12:40 p.m. ET Monday, says protesters will gather at Yonge and Dundas Square at 5 p.m. to march past the site of the shooting on their way to Toronto police's 14 Division.
Sarah Yatim hopes Sammy's Fight Back for Justice will help stop a repeat of what she sees as an injustice at the hands of police.
"Police everywhere don't have a right to mistreat us just because they have a weapon," the Facebook group says.
Family hiring lawyer
Yatim's father, Bill, questioned why police fired nine rounds, only to then use a Taser.
He declined a full interview but said his family is getting a lawyer.
The family lives in the area of Sheppard and Victoria Park avenues, and moved to Canada from Syria about five years ago. Yatim had recently graduated from high school.
A neighbour, Valentine Rociu, said Yatim was a good kid who was "extremely calm."
Police chief Bill Blair, during a news conference where he sought to assure Torontonians that he wanted answers to the shooting as much as they do, said the police force was reaching out to the family.
"As a father, I can only image their terrible grief and their need for answers," Blair said.