Brazilian police say they've uncovered emails between International Olympic Committee (IOC) member Patrick Hickey and the head of a ticketing company that discussed the illegal sale of Olympic tickets.
Police told a news conference in Rio de Janeiro on Tuesday that they were also investigating bank documents for evidence of money laundering linked to the illegal ticketing ring.
Hickey, the former top European official at the IOC, was arrested in Brazil last week on charges that he took part in illegal ticket sales for the Rio Games, which ended on Sunday.
Three members of the Olympic Council of Ireland (OCI) are suspected of involvement in the illegal sales, police said: executive director Stephen Martin, secretary-general Dermot Henihan and treasurer Kevin Kilty.
The men remain in Brazil and their passports were seized by police on Sunday.
A Brazilian judge also ordered the seizure of the passports of stand-in OCI president Willie O'Brien, vice-president John Delaney, and an OCI personal assistant, Linda O'Reilly.
A court in Rio de Janeiro said earlier on Tuesday that no date has been set for a hearing for Hickey, who stood aside as head of the OCI and from all his other Olympic roles during the investigation.
Hickey, a 71-year-old Irishman, is in a maximum-security Rio prison following a police raid last week at his hotel on suspicion he participated the illegal sales plot.
Police allege Hickey was part of a scam involving Ireland's official Games ticket reseller, Dublin-based PRO10 Sports Management, and an international sports hospitality company, THG Sports.
They accuse PRO10 of funnelling tickets to THG Sports, which sold them illegally at inflated prices. A director of THG Sports, Kevin Mallon, was arrested this month in Brazil and is now sharing a cell with Hickey in the Bangu 10 prison.