Then, they busted the Silk Road, an online drug marketplace that used bitcoin, the world’s most popular digital currency. And, now, they’re really starting to think hard about this new breed of internet money.

On Monday, bitcoin and other digital currencies will come under the glare of the Senate Committee on Homeland Security and Governmental Affairs. And ahead of next week’s hearings, the five federal agencies with the most skin in the virtual currency game sent the Committee their take on this hot-button issue. According to letters penned by the agencies — which the Committee made available on Friday (see below) — all five are watching these currencies very closely, though some realize internet money has very legitimate uses that have nothing to do with criminal activity.