The Fiji police commissioner, Commodore Esala Teleni, says a former parliamentarian, Peceli Rinakama, seized by soldiers a week ago is still in custody.
There had been no official word about the military's action but Commodore Teleni has now told the Fiji Sun that Mr Rinakama is under investigation, adding that the information is sketchy.
It remains unknown why and where he is being held and by whom.
The interim regime is refusing to take any questions.
The military command says questions about Mr Rinakama have to be directed to the permanent secretary for information, Lieutenant Colonel Neumi Leweni, who in turn refuses all comment on the matter.
The Australia-based Fiji Democracy and Freedom Movement has expressed its concern about the fate of Mr Rinakama, given the military's human rights violations since the 2006 coup.
Since last April, the interim regime has been ruling with emergency powers, allowing the military to detain individuals deemed to be a threat to the nation's security.