On Monday, the FBI had announced a new television campaign aimed specifically at women, in the hopes of tracking down Greig, hoping she could lead agents to Bulger.
The infamous duo have been on the run together since 1995.
According to the FBI's website, Bulger was being sought in connection with murders committed from the early 1970s through the mid-1980s during his leadership of organized crime. Some of the crimes listed in connection with Bulger include conspiracy to commit murder, conspiracy to commit extortion and narcotics distribution, among others.
Bulger, a former FBI informant, went on the run in the mid-1990s after he was allegedly tipped off by a now-disgraced ex-FBI agent that he was about to be indicted. The FBI agent, John Connolly Jr., was convicted in 2008 for his role in a mob hit in 1982 while he was supposedly undercover.
The Winter Hill Gang allegedly raked in income from extortion payments paid by career criminals in the Boston area in exchange for the ability to run drug operations, loan sharking and other illegal enterprises.
ABC News' Lee Ferran, Michael S. James and The Associated Press contributed to this report.