Police in Brazil have arrested the head of the European Olympic Committees, Irishman Patrick Hickey, in Rio over illegal Olympic ticket sales.
Mr Hickey, 71, is suspected of being involved in a scheme to sell tickets for higher than their face value.
He was taken to hospital after his arrest as a precaution, where he will probably spend the night, police said.
When officers went to his hotel room on Wednesday morning they found his wife there with his Olympic credentials.
Mrs Hickey said her husband had left for Ireland at the weekend, police told a news conference.
With the help of the hotel they began a search and found Mr Hickey in the room next door, they said.
While police said they had reason to believe he was trying to escape, a video apparently of the arrest on the ESPN Brazil sports news website shows Mr Hickey answering the door naked to officers.
Police said the arrest was related to that of fellow Irishman Kevin James Mallon on the day of the Olympic opening ceremony.
They estimate the potential profits of the alleged scheme at 10m reals (£2.4m; $3.1m).
The International Olympic Committee (IOC) said it would co-operate with any police investigation.
Irish broadcaster RTE reports that Mr Hickey faces three potential charges: facilitating ticket touting, forming a cartel, and “ambush” marketing.
A spokesman for Ireland’s Department of Foreign Affairs and Trade told the BBC: “We are aware of an Irish citizen having been arrested in Rio. The department, through its consulate in Rio, is following up and stands ready to provide all appropriate consular assistance.”
Sports minister Shane Ross, who is in Rio and who met Mr Hickey at the weekend to discuss the ticket sales allegations, tweeted simply: “Shell shock here in Rio.”
The OCI said in a statement it was “aware of the media stories regarding Pat Hickey and we are seeking total clarity on the situation before we comment further”.
Irish minister wants independent inquiry into Olympic ticket sales
Mr Hickey is president of the European Olympic Committees, the body which gathers the continent’s 50 national Olympic committees together.
His passport and Olympic ID were seized and were later displayed to photographers at the press conference.
Mr Mallon is the director of THG Sports, a sports hospitality company alleged to have resold tickets for Rio 2016 illegally.
When Mr Mallon was arrested on 5 August, he was found to be in possession of more than 800 top-class tickets for the Games.
Tickets of the Rio 2016 Olympic Games seized to one of the directors of THG Sports, a company of international business events and information group Marcus Evans, Irish Kevin James Mallon, are displayed during a press conference at the City PoliceImage copyrightAFP
Police suspect they were to be sold at prices of up to £6,000 ($7,800) each.
THG Sports said Mr Mallon had not sold or sought to sell tickets but had been holding them for collection by clients of the Irish authorised ticket reseller, Pro 10 Management.
THG Sports is owned by Marcus Evans Group, which also owns Ipswich Town Football Club.
Marcus Evans was one of four names on a list of arrest warrants issued by a Brazilian judge on Monday in connection with the alleged reselling of Rio 2016 tickets.
None of those four people is thought to be in Brazil and police there have said they will pursue the matter with Interpol.
A further three arrest warrants were issued on Wednesday, Brazilian police said, for directors of Pro 10 Management.
The OCI said it would launch an inquiry into the ticket sale controversy but has been criticised for rejecting a call by the Irish sports minister to bring in independent investigators.
Last week, the OCI wrote on its website there was “absolutely no suggestion of misconduct or impropriety” by the OCI or any of its staff.
Mr Hickey was elected head of the European Olympic Committees in 2006 and has been in charge of the Olympic Council of Ireland since 1989.
He has also been on the International Olympic Committee’s executive board since 2012.
Country G S B
U S A 28 30 28
Britain 19 19 12
China 17 15 19
Russia 12 12 15