Devon and Cornwall Police said the investigation was ongoing and due to the complexity of the case inquires were expected to take several months.
Detective Constable Glenn Harrop said; "We believe there are potentially hundreds of victims from across the country."
Two women from Tavistock have been arrested by police investigating an alleged European music festival ticket scam.
The women, aged 50 and 21 were arrested on suspicion of fraud by misrepresentation by officers from Devon and Cornwall Police.
The force is investigating an allegation of fraud surrounding the sale of tickets for Tomorrowland 2013 - an electronic music festival held near Antwerp, near Belgium in July.
Police believe there could potentially be hundreds of victims from across the country and are urging anyone who thinks they have been scammed to get in touch.