A news release from Greek police says the Canadians are suspected of beating a 41-year-old Greek man on June 7.
It says the man suffered a grievous head injury and was taken to a hospital in Athens.
Michael Tucker with the Alberta Law Enforcement Response Team describes the attack as "near-fatal."
He says the men — who are 29, 34, and 35 — were in Greece at an international convention for the outlaw biker gang.
The agency is helping foreign investigators by providing them with information about the suspects.
Two of the accused are members of the club's Westridge chapter in Edmonton and the other is with the Nomads in Red Deer, Tucker said Thursday.
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