A federal grand jury in Boston is investigating the 16-year period when James "Whitey" Bulger and his girlfriend, Catherine Greig, were fugitives living in California, according to the Boston Globe.
According to the Globe, the FBI has issued at least two subpoenas: one to Bulger and Greig's former property manager in Santa Monica, and one to someone who knew the couple during their time in California.
The federal investigation could lead to further charges against Bulger and Greig, the Globe reports.
Bulger, a reputed South Boston mob boss who faces charges on 19 counts of murder in addition to other charges, was arrested on June 22 in Santa Monica and brought to Boston for trial.
Greig, who lived with Bulger in California, faces charges of harboring a fugitive.