Hickey, 71, also head of the European Olympic Committees and an International Olympic Committee (IOC) member, has been held in a Brazilian top security prison since police raided his Rio hotel on August 15 during the Olympics as part of their probe into the affair.
Warrants for the arrest of four others were issued including Marcus Evans, a British businessman who is also the chairman of Ipswich football club in England.
"The analysis of the pieces of evidence, and above all of the emails, confirm that the president of the Irish Olympic Committee, Patrick (Hickey), was in direct contact with Marcus Evans, who is the head of THG," Rio police investigator Ricardo Barbosa told a Rio press conference Tuesday.
Hickey and another suspect Kevin Mallon, arrested on August 5, are being held at Rio's Bangu 10 prison while arrest warrants had been issued for seven others who are on the run including Evans, police said.
More From This Section
The scandal has been mounting since the arrest of Mallon, an Irish director of THG.
Police said they seized hundreds of tickets from Mallon, some of which had the Olympic Council of Ireland name on them.
As part of the probe Rio police on Sunday raided the offices of the Irish delegation in the Rio Olympic Village and seized passports from three Irish Olympic officials. They also confiscated phones and computers, Irish officials said.
Passports seized belonged to Kevin Kilty, head of the Irish delegation in Rio, Dermot Henihan, secretary general of the Olympic Council of Ireland, and Stephen Martin, police said in a statement.
Evidence linked the three to the illegal ticket scam, police said.