Gary Alford, U.S. Internal Revenue Service special agent, testified in the ongoing Silk Road trial, that the site paid thousands of dollars to hackers who threatened the site with DDoS attacks as well as threats to leak vulnerabilities.

The info came from emails subpoenaed from defendant Ross Ulbricht as part of the investigation. Ulbricht is on trial at the U.S. District Court for the Southern District of New York for narcotics and criminal enterprise charges in relation to Silk Road.

On at least two separate occasions, Silk Road operators paid malicious attackers ransoms in exchange for keeping the site up and secure.

One of the emails entered into evidence came from a user who offered info on a serious vulnerability in the site’s software. The offer was for $5,000 for the flaw and $15,000 to offer full details on how the flaw operated and how it could be exploited.

The seized computer belonging to Ulbricht indicated that the $15,000 was paid with the notation: “pay off hacker.” Silk Road also paid off a hacker that threatened a DDoS attack to the tune of $10,000.

The case is being overseen by District Judge Katherine Forrest of the Southern District of New York.