(CNN) -- The longtime companion of notorious fugitive James "Whitey" Bulger pleaded not guilty in Boston Thursday to charges she harbored and concealed him, said a spokeswoman for the U.S. Attorney for the District of Massachusetts.
Catherine E. Greig, 60, who is being held without bail, allegedly assisted Bulger from January 1995 until June, when the pair was arrested in California, the U.S. Attorney's Office said in a statement last week.
"It is alleged that Greig conspired to take steps to prevent Bulger's discovery and arrest, after knowledge of the fact that a warrant had been issued for his apprehension," the office said.
Greig's attorney, Kevin Reddington, did not immediately return calls for comment Thursday.
According to the indictment, Greig and Bulger posed as a married couple under different false identities and claimed to be from states other than Massachusetts. She would shop and handle bills so that Bulger would "minimize his time in public," it asserts.
Government prosecutors last month released a series of photographs showing cash, weapons and even a grenade recovered from the Santa Monica, California, apartment where Bulger and Greig apparently lived for 15 years while he was being hunted by the FBI.
If convicted of the charges against her, Greig could be sentenced to five years in prison, three years of supervised release and a $250,000 fine, according to the U.S. Attorney's office.
Bulger has pleaded not guilty to all counts against him, including his alleged role in 19 murders.
Prosecutors say Bulger was the head of a South Boston Irish gang before he fled an impending racketeering indictment in 1995.
CNN's Katie Silver contributed to this report