The Australian tax authority is using data matching programs to view complex cryptocurrency transactions. The Cybercrime Squad however says exchanges are used to launder money by drug dealers, thieves, fraudsters and terrorists.

https://www.news.com.au/national/breaking-news/ato-wades-into-chaotic-cryptocurrency-web/news-story/bf1d41f9aec58338b6b9afb50ed0d8a9