A 13-year-old boy has been found not guilty of assaulting and robbing Mitchell Wilson, an 11-year-old Pickering, Ont., boy who took his own life.

The boy was accused of the assault and robbery in November 2010.

Judge Mary Teresa Devlin said it could not be proven beyond a reasonable doubt that the accused was the one responsible for the attack.

Mitchell's father Craig Wilson said he was disappointed with the verdict, but "the law is the law."

"I believe they followed the law right to the letter [and] I don't think Mitchell would have liked to have seen the law bent for his own benefit," Wilson said outside court.

"For that reason, I think we walked out respectfully with our heads held high."

Wilson, who had muscular dystrophy, was required to take walks to keep his disease at bay and sometimes used a walker for assistance. The Crown alleges it was during one of those walks when the accused jumped Mitchell, breaking some of his teeth and taking his father's iPhone.

The accused cannot be named because of his age.

Wilson's family said he committed suicide after learning he would have to face his alleged attacker in court.

Wilson was found dead in September 2011 with a plastic bag tied around his head.

Mitchell's father said his son suffered panic attacks and severe depression following the assault.

Judge Devlin ruled in mid-February that statements Mitchell Wilson had made to police before his death could be admitted as evidence.

On Monday, however, Devlin said Mitchell's identification of the accused could have been faulty, and therefore she had no choice but to issue the acquittal on charges of assault causing bodily harm and robbery.

"They say eyewitness accounts or identification are unreliable," Wilson said. "I know Mitchell was 100 per cent sure in his mind and I like to think that's the truth."

"Karma always comes around to get the ones that get away."

Mitchell's aunt Cheryl Wilson said people should be encouraged to come forward about bullying.

"If someone is bullying you, if someone is harming you or breaking the law and making you feel terrible about yourself, you need to speak up, regardless of the outcome," she said. "It's the process not the product."

Mitchell's aunt added that the family had wanted Mitchell's voice heard.

"I don't think we were looking for any sort of retribution or anything," she said. "Since he wasn't here, we were here as a family to follow it through court right from the beginning until the end."

She also said the family was leaving court with "the same great memories we had coming in of a wonderful little boy."

With files from The Canadian Press