A dark web tycoon pleads guilty. But how was he caught?

The FBI found Eric Marques by breaking the famed anonymity service Tor, and officials won’t reveal if a vulnerability was used. That has activists and lawyers concerned.
Read more: https://www.technologyreview.com/s/615163/a-dark-web-tycoon-pleads-guilty-but-how-was-he-caught/?source=Snapzu