Catherine Greig, girlfriend of mobster James “Whitey” Bulger, was sentenced to eight years of federal prison Tuesday, officials said.

Christina Sterling, spokeswoman for the Office of the U.S. Attorney for the District of Massachusetts, told The Daily Free Press in an email that Greig received eight years in federal prison, followed by three years of supervised release and a $150,000 fine.

Greig, 61, pleaded guilty to conspiracy to harbor a fugitive, conspiracy to commit identity fraud and identity fraud in March.

Greig was sentenced for identity theft as well as harboring and conspiring to protect and successfully protecting a criminal with knowledge that he was a criminal, according to a sentencing memorandum. Assistant U.S. Attorney Jack Pirozzolo filed the memorandum June 8 before the sentencing.

From January 1995 through June 22, 2011, Greig conspired with Bulger to prevent him from being found and arrested after learning about a warrant that had been issued for his apprehension, according to a press release from the U.S. Attorney’s Office for the District of Massachusetts.

Greig and Bulger posed as a married couple under different false identities and obtained multiple forms of ID, bought prescription medication, paid bills under an assumed name and shopped for groceries and other necessities while living together.

Greig illegally obtained and used multiple ID, including social security numbers, drivers’ licenses, and birth certificates of other real persons with intent to create false identities, according to the press release.

Authorities seized more than $820,000 in cash and 30 firearms that was hidden inside Greig and Bulger’s apartment, according to the press release.

“This is an extreme case of harboring – at least in terms of its length and the seriousness of the fugitive’s alleged crimes – as may exist in a domestic case,” Pirozzolo stated in the memorandum.

The memorandum called Greig’s case “an extreme case of harboring,” noting that the U.S. has not been able to locate any comparable cases. The prosecutors argued Greig’s role in harboring Bulger called for a “substantial period of imprisonment.”

Greig’s conduct was more harmful than protecting Bulger from law enforcement, the memorandum stated.

The U.S. recommended a sentence of imprisonment of 120 months, a fine of $150,000, a period of supervised release of three years, a mandatory special assessment of $300 and forfeiture as set forth in the plea agreement, according to the memorandum.

“[Greig’s conduct] also denied victims and family members of victims for many years the opportunity to see Bulger answer for his crimes,” according to the redacted sentencing memo.

Susan Goldberg, deputy circuit executive of the Office of the Circuit Executive, said the judge based the sentencing on Greig previously pleading guilty to charges of harboring a fugitive in March.

“The judge determined that appropriate sentence to the acknowledgement of those crimes was eight years in prison,” Goldberg said.

Goldberg, however, said the sentence might not stick.

“Technically, the sentence is appealable,” Goldberg said. “She can challenge it in the court of appeals.”