In documents from February 2013 first made public on August 29, 2015, it was revealed that in August 2010, the FBI had sent a memo to its field offices in Nevada stating that it would patrol Burning Man to "aid in the prevention of terrorist activities and intelligence collection". Although a threat assessment performed by the FBI determined that drug usage and crowd control were the only major threats to Burning Man, the Bureau still sent an unspecified number of undercover officers to the event, with "no adverse threats or reactions".