An investigation by an outside police force has found that Mounties in British Columbia who used a Taser on an 11-year-old boy should face no charges.

The incident took place on April 7 in the northern city of Prince George, B.C., as officers responded to a call about the stabbing of a 37-year-old man at the boy's group home.

RCMP asked the West Vancouver Police Department to probe how officers confronted the child. The results of that review were released Thursday afternoon in a brief letter from West Vancouver police Chief Peter Lepine.

"My team spent much of this spring and summer interviewing witnesses, collecting and analysing evidence and consulting with those in the legal profession as well as subject matter experts in topics like police use of force," Lepine wrote.

However, he did not say how investigators reached the decision not to recommend charges, only that the officers' actions did not constitute a violation of the Criminal Code.

Critics say the probe has revealed too few details about the situation at the time the boy was stunned by police.

"We've had this lengthy assessment by the external police investigators who've now told us nothing," said Michael Vonn, a lawyer with the B.C. Civil Liberties Association.

"We're not even getting basic information, like what was the officer seeing at the time. Was there a weapon involved? What were these so called volatile circumstances?"

Police psychologist Dr. Mark Webster said there has been no research on how Tasers affect children or those with heart conditions, and said the weapon "should not be in service."

An officer who had been working for the RCMP for only 18 months was placed on administrative leave following the incident, pending the police investigation.

The boy's mother said the Taser could have killed her son, who has a heart condition called cardiomyopathy and has been diagnosed as bipolar.

The Commission for Public Complaints Against the RCMP and B.C.'s children's watchdog both launched their own reviews after the boy was stunned by police.

The 11-year-old is believed to be the youngest person in Canada to be shocked by a police Taser.

According to a report by the Commission for Public Complaints Against the RCMP, between 2002 and 2009 officers with the force used a stun gun in 194 cases involving youth between the ages of 13 and 17.

The 2010 report also found that RCMP Taser shocks against youth were much more common in B.C. than in other provinces.

With a report from CTV British Columbia's Bhinder Sajan and files from The Canadian Press