US law enforcement can access details of money transfers without a warrant through an obscure surveillance program the Arizona attorney general’s office created in 2014. A database stored at a nonprofit, the Transaction Record Analysis Center (TRAC), provides full names and amounts for larger transfers (above $500) sent between the US, Mexico and 22 other regions through services like Western Union, MoneyGram and Viamericas. The program covers data for numerous Caribbean and Latin American countries in addition to Canada, China, France, Malaysia, Spain, Thailand, Ukraine and the US Virgin Islands. Some domestic transfers also enter the data set.
You need to be a member of law enforcement with an active government email account to use the database, which is available through a publicly visible web portal. Leber told The Journal that there haven’t been any known breaches or instances of law enforcement misuse. However, Wyden noted that the surveillance program included more states and countries than previously mentioned in briefings. There have also been subpoenas for bulk money transfer data from Homeland Security Investigations (which withdrew its request after Wyden’s inquiry), the DEA and the FBI.
Wall Street Journal podcast—with transcript—on the program. I think the original reporting was from last March, but I missed it back then.