SAN FRANCISCO—Corrupt Silk Road DEA agent Carl Force was sentenced to 78 months in prison today by a judge who said his difficult upbringing didn't warrant any exception to the sentencing guidelines.

"The extent and the scope of Mr. Force's betrayal of public trust is quite simply breathtaking," said US District Judge Richard Seeborg. "It is compounded by the fact that it appears to have been motivated by greed and thrill seeking, including the pursuit of a book and movie deal."

Force investigated the Silk Road drug-trafficking as part of a Baltimore-based task force. Force took on additional personalities that weren't authorized by his bosses. Using one called "Death From Above," he tried unsuccessfully to extort Ross Ulbricht, who earlier this year was convicted of being Silk Road boss Dread Pirate Roberts and sentenced to life in prison . In another online persona, "French Maid," Force convinced Ulbricht to pay him for "law enforcement counter-intel."

Information about Force and another corrupt agent was kept out of Ulbricht's Silk Road trial. Force was arrested after that and pled guilty in June.

Seeborg's sentence was less than the 87-month sentence the government requested, but it's substantially more than the 48 months that Force's defense lawyer asked for.

In addition to his crimes involving Ulbricht, Force ripped off a customer of CoinMKT, a Bitcoin-related company he was illegally moonlighting for. He stole $370,000 from a CoinMKT customer, putting $37,000 in a government account and keeping the rest for himself. As part of his sentence, Force was ordered today to pay $337,000 in restitution to the victim, identified only as "RP." He was ordered to pay $3,000 to Curtis Green, a former Silk Road staffer who Force's team arrested.

During the sentencing hearing, Force's lawyer Ivan Bates said that while his client accepted responsibility for his crimes, the judge should take into consideration Force's mental illness and family history of alcoholism and abuse.

"There’s no doubt he’s going to jail," said Bates. "He's lost his career. He's lost his marriage, he’s lost everything he’s had. He’ll always have a life sentence because of the mental health issues he has."

Bates also said that Force shouldn't have been doing undercover work at all. An undercover mission in Puerto Rico in 2008 caused him to have a "break from reality," after which he was institutionalized. Force wasn't allowed to return to his work at DEA until 2010.

"The notion that Mr. Force should get a reduction because he was operating in a stressful environment and has mental health issues, that would send an incredibly dangerous message," countered prosecutor Kathryn Haun. "Many federal agents operate in stressful environments. It's a stressful job."

Force is barred from communicating with Shaun Bridges, the other agent in the Baltimore office who was convicted of stealing from the Silk Road during the investigation. Bridges is scheduled to be sentenced in December.