Those messages had been sent through servers located in the United States. British law prohibits prosecutors from introducing intercepted electronic communications at trial but if the e-mails could be obtained legally by the U.S. government, they could be shared with the British. A DOJ spokesman told National Journal that following "requests for information from the United Kingdom...court orders were obtained and served, and we were able to provide [the] information obtained pursuant to the court orders."

It has been reported by several British newspapers that the e-mails were held by Yahoo, and that a court order for the messages was issued in California, where the company is based. The Justice spokesman said the U.K.'s request was made under the Mutual Legal Assistance Treaty, which allows two countries to gather and share information in a criminal case. According to British press reports the e-mails were initially intercepted by the National Security Agency in 2006, while the conspirators were under intense, around-the-clock surveillance by British authorities.