Tonga's police commissioner says an internal investigation has identified serious shortcomings in the lead-up to an American fugitive escaping Vava'u in September.
Dean Jay Fletcher, who has been charged with the murder of his wife, escaped from a police station in September and fled on a yacht to American Samoa where he was arrested.
The commissioner, Steve Caldwell, said there were serious shortfalls in accepted procedures around the management of prisoners.
The police have refused to go into further detail about the shortfalls, saying that the case is under active investigation.
Five police officers on Vava'u are now under investigation and face possible disciplinary action.
Fletcher appears in Pago Pago court
Meanwhile, an American Samoa judge has denied a motion for Mr Fletcher's charges of entering the territory illegally to be dismissed.
The prosecution claims that Mr Fletcher sailed into Pago Pago harbour, and then tried to leave again, early last month without obtaining the necessary permits.
He is being held without bail for entering American Samoa without proper clearance and proof that he was cleared from his last port of call, Tonga.
The Tongan government has been in discussions with the US State Department to extradite Mr Fletcher back to Tonga to face the murder charge, and a delegation of Tongan police visited the territory this week.
Mr Fletcher is due to face a pre-trial hearing on 22 November.