Three senior Olympic Council of Ireland officials, including one from Northern Ireland, have had their passports, cellphones and laptops captured in Brazil.
RTÉ and the Irish Times say the officials comprise OCI chief executive Stephen Martin – an Olympic gold medal winner – from Bangor, County Down.
The OCI has named a crisis management committee to lead its response to Brazil.
A former hockey player, Mr Martin, was formerly a director of coaching at Ulster Hockey.
The two other executives are reported to be Ireland’s Olympic chef de mission, Kevin Kilty and OCI Secretary General Dermot Henihan.
No arrests were made during the investigation on Sunday. Brazilian police are trying to acquire the passports of three other individuals linked to the OCI.
RTÉ says the development is part of an investigation that is on-going and there’s nothing to imply impropriety on the part of any of those involved.
In a statement released overnight, the OCI said it was appointing a disaster management committee to direct the council’s response to events in Brazil.
The three folks in the committee are Prof Ciaran O’Cathain, Swim Ireland, Sarah Keane, Athletics Ireland, Snowsports Association of Ireland, and Robert Norwood.
The statement said an international accountancy company would be requested to run an independent review of ticketing arrangements in Rio.
Its work will begin immediately and the firm will be selected and its terms of reference will be published.
Its report will be presented to a judge who will chair the state inquest into the OCI’s management of ticketing at the Rio Olympics, the statement said.
“The OCI had an allotment of unused official tickets in their own offices which had been made available for athletes’ families and friends. The police also took possession of these tickets,” the OCI said.
He has been held alongside THG manager Kevin Mallon at Rio’s Bangu 10 penitentiary.