Fiji's Police Commissioner Ben Groenewald says if he finds police personnel deliberately closed an investigation involving allegations against security personnel, he'll take steps against them.
Early last year, authorities promised an investigation following the release of a clip online showing the severe beating of two recaptured prisoners.
The incident prompted the New Zealand parliament to pass a motion condemning torture.
In July, the Police Chief of Operations said the file was closed, but a week later the new Police Commissioner reopened the case.
Mr Groenewald believes an administrative error led to it being closed but says if it was deliberate he can take action under the Police Act.
"If they are or not involved in the crime and they deliberately close up the file I will take departmental steps and they will appear before a tribunal and they will be charged and in the end I will make a decision on what will happen to those people," he says.
He has given investigators until the end of the month to review the case.
Last year, the Fiji Prime Minister Frank Bainimarama declined to condemn the violence, but instead defended the work of security personnel protecting citizens from hardened criminals.