GREELEY, Colo. -- Greeley Mayor Ed Clark will not face criminal charges after the family of a 15-year-old boy accused him of throwing the teenager to the ground because he refused to stop riding his motorbike.

The Larimer County District Attorney's office said it could not meet the burden of reasonable doubt in prosecuting the case. They made the announcement Friday. Clark could have been charged with assault.

"In order to prevail at trial, the People are required to prove the allegation beyond a reasonable doubt," District Attorney Larry R. Abrahamson said in the statement. "Given the facts of this case, as revealed by the investigation and applicable statutes, the People cannot meet that burden and charges are not appropriate."

Prosecutors also say they won't prosecute the boy's mother, who was being investigated for contributing to the delinquency of a minor for allowing him to ride the motorbike.

The teen was ticketed for driving the motorbike without a license and operating an off-road vehicle on the street. His case is still pending.

"We make no judgment on the appropriateness of the actions taken by any of the parties involved; our only responsibility was to assess the criminality of the acts under Colorado law," Abrahamson said.

Abrahamson said his office met with the boy's family before making the decision.

A judge had granted the boy's family a restraining order against Clark after the incident. The restraining order requires Clark to stay at least 100 yards away from the boy.

Clark had said he stopped the boy for his own safety and did not hurt him. The incident occurred on June 23 in the area of 74th Avenue and 22nd Street, in Clark's neighborhood.

Larimer County investigated the case instead of Weld County because Clark worked part-time as a special investigator with the Weld County DA's office there.

He resigned earlier this week. He was paid to look into juror summons issues. Clark works as security director for University Schools during the school year.