Tonga's Police Commissioner, Grant O'Fee, says the criminal records of 172 people which were wiped included grievous bodily harm and one manslaughter case.
Police and the Solicitor General launched investigations in February after it was revealed that 172 people over a ten-year period to 2011, had their records cleared by police officers.
Most of the cases involved people with minor convictions wanting to apply for Visas to New Zealand and Australia.
Mr O'Fee says their investigation has found that a previous Minister of Police, who has since passed away, made it known to many senior staff that is was okay to give clearances.
"I think what his intention may have been was to allow people with minor offences another chance like you would get in New Zealand under the Clean Slate legislation. The problem I have is that was never intended to encompass such offences such as grievous bodily harm and manslaughter."
Grant O'Fee says three members of the police have been identified as approving such clearances and could face sanctions from counselling through to dismissal.