More than a year after man suffered broken ribs while in custody at the Yellowknife detachment, Mounties say they've been cleared of any wrongdoing following an external investigation.

In the early hours of July 18, 2017, the prisoner was transported from cells to Stanton Territorial Hospital. Once back in custody, police say the man became uncooperative and resisted officer's attempts to place him back in cells.

"The male acquired non-life threatening injuries while in custody," states spokesperson Marie York-Condon in a news release issued Thursday.

The man "had fractured two ribs while in custody," states the release. He was charged with assaulting a police officer, uttering threats and breach of probation as a result of the incident.

The in-custody injury triggered an external investigation led by Edmonton Police Services. On Thursday, Yellowknife stated the probe determined the officers involved were "clearly lawfully placed and acting properly in the execution of their duties."

"There was no evidence to support any inference that police engaged in any unlawful or unreasonable conduct that would give rise to an offence,"

"The force used was necessary and reasonable in all circumstances," states the news release.

The investigation is now closed.