The fatal police shooting of Toronto teen Sammy Yatim reignited burning questions about the use of lethal force, particularly for those who have lost loved ones to similar tragedies.

On Monday, angry protesters marched in Toronto asking why police used lethal force against a lone teen brandishing a three-inch knife, who was isolated in an empty streetcar, and surrounded by as many as 23 officers.

David Boyd's son Paul was fatally shot by Vancouver police in 2007, and Katherine Yu's brother Edmond died after a 1997 confrontation with Toronto officers.

They believe a more nuanced police response could have saved lives, both for their own loved ones and for Yatim.

David Boyd and Katherine Yu joined CBC Radio's The Current to share their stories and views on how police can defuse tense situations to prevent needless deaths. Listen to the full interview above.