Secretary of State Treasury Department Steven Mannchin has announced that his department is investigating the illegal applications of Chief Bitcoin Cryptocurrency. He said that the objective of the survey was to ensure that digital currency has not been used for "illegal purposes".
During an interview with Yahoo Finance in the beginning of November 2017, the Secretary claimed that the alleged abuse of Bitcoin should be "very carefully" checked to ensure that the Black Web has not been funded by bitcoins. .
Source https://cointelegraph.com/news/us-treasury-department-investigates-illegal-uses-of-bitcoin