The U.S. Department of Justice’s conviction of Silk Road mastermind Ross Ulbricht may have been compromised by two corrupt investigators.

U.S. Drug Enforcement Administration agent Carl Force will plead guilty to extorting more than US$450,000 from the Silk Road online underground marketplace during his investigation of the site.

Force, who was a U.S. Drug Enforcement Administration agent, is the second federal officer who has been charged with taking money from the marketplace.

Last week, ex-Secret Service agent Shaun Bridges, who worked with Force on the same task force, reached a plea bargain with prosecutors, for funneling money from Silk Road during the course of the investigation.

Force will plead guilty to extortion, money laundering and obstruction of justice, according to court papers filed Monday with the U.S. District Court for the Northern District of California.

Last month, Silk Road creator Ross Ulbricht was sentenced to life in prison for his involvement with Silk Road, which federal authorities estimated generated over 1.2 billion in drug sales between 2011 and 2013.

Ulbricht’s lawyer, Joshua Dratel, did not return immediate requests for comment though has stated at press conferences that the federal agents’ misconduct could possibly play a role in Ulbricht’s appeal, given how their actions may have damaged the integrity of the government’s case against Ulbricht.

Both Force and Bridges were part of an undercover multi-agency task force investigating Silk Road prior to the operation’s bust in October 2013.

During the course of his Silk Road investigation, Force had the DEA freeze an online, $297,000 account of one of the site’s users, the DOJ says in court documents. He transferred the money into his personal account, rather than to the DEA, according to the DOJ.

Force also defrauded Ulbricht at least twice in 2013, using a number of pseudonyms on Silk Road, the DOJ says.

As “French Maid,” Force talked Ulbricht into paying $98,000 for inside information about federal investigations into Silk Road. Then, as a drug dealer named “Nob,” he convinced Ulbricht again to pay $50,000 to reveal investigation information, the DOJ said.

In both cases, Ulbricht’s funds were transferred into Force’s personal account, according to court documents. All the transactions were conducted in the bitcoin digital currency, which was the sole method of payment for Silk Road.

Bridges, who was charged with money laundering and obstruction of justice, took more than $800,000 worth of bitcoins from Silk Road, using a highjacked administrator account, the DOJ said.