TORONTO -- A Toronto police officer was found guilty of attempted murder Monday in the shooting death of a troubled teen on an empty streetcar, a verdict the teen's mother called a first step in changing the way police deal with people in crisis.

After six days of deliberations, an 11-member jury cleared Const. James Forcillo of the more serious charge of second-degree murder in the 2013 death of 18-year-old Sammy Yatim, an incident that sparked public protests in the city.

"Sammy was a young man who had his whole future ahead of him," Yatim's mother, Sahar Bahadi, said moments after the verdict was read out. "Because of what the police did we lost him forever."

Forcillo's lawyer indicated the defence would try to have the proceedings stayed -- which would prevent a conviction from being registered -- claiming abuse of process.

"We say the abuse of process is Const. Forcillo substantially followed the police training he was given and so if the state gave him that training, they should not be entitled to a conviction in the matter," Peter Brauti said outside the courthouse. "This is Phase 1 of a long road for us."

Forcillo, who remains out on bail, showed little emotion as his verdict was delivered, maintaining the same stoic expression he's held throughout the trial.

Yatim's mother, who was seated in the front row of the courtroom, later called the verdict an opportunity to change policing.

"For me, it's the first step. I would now like to be part of the discussion to change the police training policies when dealing with people in crisis so this painful incident does not repeat again," Bahadi said.

Forcillo's case will be back in court in mid-May, when Brauti will argue for the stay of proceedings.

He will also bring a constitutional challenge to the mandatory minimum sentence Forcillo faces after being found guilty of attempted murder, which is four years in prison. An appeal in the case is also being considered.

"It's early days still for officer Forcillo, he's still got a lot of fight ahead of him," Brauti said.

Brauti added that he believed the outcome of the verdict could have been changed if he had been allowed to present the jury with a "suicide-by-cop" theory, which the judge did not allow at trial.

That theory suggested Yatim was depressed and didn't comply with police orders because he didn't care about his own life and was prepared to act in a way that would lead to police actions resulting in his death.

"We thought the suicide by cop was a huge part of our defence," said Brauti. "We were shocked and disappointed we weren't allowed to put that to the jury and I believe it would have had an effect."

Forcillo, 32, had pleaded not guilty to second-degree murder and attempted murder in Yatim's death, which was captured on cellphone videos that went viral online.

The public outrage over the incident prompted the city's police chief to launch a review of officers' use of force and their response to emotionally disturbed people.

Crown prosecutors had argued Forcillo's actions weren't necessary or reasonable, while his lawyer called those actions justified and carried out in self-defence.

The jury heard that Yatim had consumed ecstasy at some point before boarding the streetcar. Videos showed him exposing himself and pulling out a small knife, causing panicked passengers to pour out of the vehicle when it came to a stop.

Forcillo -- the first officer on the scene -- screamed repeatedly at Yatim to drop the knife, but the teen refused and swore at police, court heard.

When Yatim took a few steps back from the top of the streetcar steps, Forcillo issued a warning for him not to take another step forward. Yatim then moved back to where he had been standing and Forcillo fired three times, causing the teen to collapse.

The jury has heard that Forcillo then fired six more shots at Yatim.

The entire encounter lasted about 50 seconds. Yatim was hit by eight out of nine bullets fired by Forcillo.

The second-degree murder charge against the officer relates to the first three shots he fired, while the attempted murder charge pertains to the second volley.

Some lawyers who followed the case said it appeared jurors tried to reach a compromise.

The verdict suggests jurors believed the first round of shots -- which led to Yatim's death -- was fired in self-defence, but found the second volley was unjustified, the lawyers said.

"What the jury must've found was that he didn't intend to kill him with the first three shots… but they must have found that he did intend to kill him with the second set of shots, but because those shots were not and could not have been fatal, that's why it's an attempted murder," said Scott Reid, a Toronto defence lawyer who followed the case.

The Toronto police union said it was concerned about the jury's decision.

"It sends a chilling message to our members and that's going to be a challenge for our frontline members to deal with this issue," said union president Mike McCormack."It has definitely impacted the psyche of frontline officers."

Toronto Police Chief Mark Saunders said he couldn't comment on the verdict, but pledged to improve the force's relationship with those with mental health issues.

"We are all going forward in time to see what we can do to reduce any harm to anybody we deal with who's a person in crisis," Saunders said.

- With files from Paola Loriggio.