More than 100 people were arrested in what the London’s Metropolitan Police calls “the UK’s biggest ever fraud operation” after taking down a fraud website called iSpoof used on 200,000 potential victims in Britain alone. Scotland Yard’s Cyber Crime Unit worked in cross-national cooperation, including authorities in the U.S. and Ukraine, to take down the site this week. In a 20-month period, the Met police claims the operation earned the criminals almost £3.2 million ($3.9 million). Tracing bitcoin records, which was used to pay for iSpoof’s services, allowed the Cyber Crime Unit to narrow down suspects.