A former Toronto police officer who shot a teen on an empty streetcar told a coroner's inquest today that having a stun gun would have "changed everything."

James Forcillo is testifying at the inquest into the death of 18-year-old Sammy Yatim, who he shot during a confrontation in July 2013.

Asked what could have helped him make better decisions that night, Forcillo said having a stun gun would have made "a world of difference," but only frontline supervisors had access to them at the time.

He argues that was a "giant failure" on the part of the Solicitor General, but one that has since been remedied as stun guns are more widely available to frontline officers.

Yatim was alone on a streetcar holding a small knife when Forcillo shot him. The teen was hit by two rounds of shots.

At his criminal trial, he was found not guilty of second-degree murder related to the first round of shots, which court heard was fatal, but was found guilty of the lesser charge of attempted murder related to the second round.

Forcillo was sentenced to six and a half years behind bars and was granted full parole in 2020.

Jurors have been told that the inquest is meant to explore issues related to police decision making and best practices in dealing with people in crisis, but not to review the events of that night or Forcillo's potential culpability.