Two people have been arrested after Beyonce fans were among hundreds of people caught in a fake ticket scam.
Police said "several" fans were turned away from the American singer's concert in Manchester in February after using forged tickets they had bought online.
A man, 31, and a woman, 55, from North Weald, Essex, were arrested on suspicion of conspiracy to defraud and have been bailed until November.
British Transport Police said there would be more "victims and suspects".
Similar offences involving other concerts and events have been discovered around the country.
Det Con Mike Dermody said: "In each case the victims believed they were buying genuine tickets and arranged to meet the seller at locations near to the venue where they handed over cash in exchange for the tickets.
"The fraud only came to light when the victims tried to enter the concert venue and security staff noticed the tickets were fakes.
"There is no doubt that there are still victims and potential suspects we haven't yet spoken yet."