The U.S. Justice Department’s seizure of a record $3.6 billion worth of allegedly stolen bitcoin, and its arrest of a married couple accused of laundering the money, was a clear demonstration of the federal government’s growing ability to police cryptocurrency transactions, according to attorneys who work the industry.

Federal prosecutors and law enforcement alleged they were able to trace funds stolen during the hack of a bitcoin exchange in 2016 that were transferred into cryptocurrency “wallets,” then into a dark web marketplace and eventually into traditional financial accounts tied to a Manhattan couple. The couple, Ilya Lichtenstein and Heather Morgan, was each charged Tuesday for their alleged role in the  $4.5 billion money laundering scheme.