A Saskatoon police officer accused of assaulting a 14-year-old boy was found not guilty Friday.

Const. Luke St. Onge was charged with assault causing bodily harm and assault with a weapon following a May 2012 incident in which he admitted to punching and pepper-spraying a teen.

He was found not guilty in Saskatoon provincial court on both accounts.

The ruling was a relief for St. Onge.

"It's been very difficult. He has had this hanging over his head. He hasn't been working. It's been psychologically, emotionally, very difficult for him. We're very happy with the result and he can put this behind him" said defence lawyer Brad Mitchell.

Court heard during the trial that while St. Onge was on patrol May 27, 2012, he was pepper-sprayed by an attacker.

A teen matching the description of the suspect was later chased down by police.

St. Onge admitted to court he punched and pepper-sprayed the suspect, who was 14 at the time and who was being held down by other officers, because he thought the boy was armed and resisting arrest.

The teen, who was missing from his group home and ran when approached by officers, testified he was punched in the face between 10 and 15 times. St. Onge said he punched the boy three to five times.

The teen testified that his left eye was swollen shut for up to two weeks after he was hit and that he had extensive bruising to the left side of his face and his right ear. He was not carrying a weapon at the time.

The defence argued officers had reason to believe the teen was carrying a weapon and resisting arrest because he was squirming and refused to move his left arm from underneath him after police tackled him.

The defence said St. Onge followed proper police protocol, which calls for force if someone is resisting arrest and the use of pepper spray if someone continues fighting.

Judge O'Hanlon said Friday there were inconsistencies in the teen's testimony and that he didn't think St. Onge was looking to retaliate. He ruled St. Onge's actions were reasonable since the boy was thought to be armed.

"Simply stated, (the boy) was resisting bringing his arm out. He had chosen to run from the officers when he knew he was being pursured," O'Hanlon said.

The boy was never charged.

St. Onge has been suspended with pay since November 2012. He will return to patrol after updating his training, a Saskatoon police spokesperson said.

--- with files from the Canadian Press