The Federal Bureau of Investigation paid the reward money to Anna Bjornsdottir, a one-time model and Miss Iceland 1974 who had gotten to know Bulger's girl friend Catherine Greig after the two women both took a shared interest in a local stray cat while the fugitive couple hid out in Santa Monica.
But it was Bjornsdottir, the newspaper reported, who recognized Bulger in a news report this summer while she was back in Reykjavik and called authorities.
After the tip, Bulger and Greig were arrested in June without incident at their Santa Monica apartment building in June. Property records showed they moved into a two-bedroom unit in April 1998, playing $863 a month.
Authorities have said they found about 30 firearms and $822,000 in cash hidden in the walls of their apartment.
The FBI had said in September it had paid $2.1 million to "more than one individual" for information that led to the arrests of Bulger and Greig, but had not given more detail.
The newspaper reported Bjornsdottir had collected $2 million of the $2.1 million in FBI rewards for her tip.
A spokesman for the FBI's Boston office said he could not discuss people who gave the bureau information.
Bulger had fled Boston after hearing from a corrupt FBI agent that he was about to be indicted. Greig joined him a short time later and has been charged with harboring Bulger as a fugitive.
Past Boston FBI officials had used Bulger as an informant for years against other organized crime factions and, later investigations found, tolerated or enabled his own ongoing criminal activities in what an appeals court in a related case earlier this year termed an "unholy alliance."
Bulger, who for years led the Boston-based Winter Hill Gang, faces charges that include 19 alleged murders from the 1970s and 1980s. Both Bulger and Greig have pleaded not guilty to the charges against them.
Through her husband, Bjornsdottir declined to speak to the Globe, the newspaper said. She had moved to Southern California in the late 1970's and appeared in cosmetics commercials. More recently she had befriended Greig after noticing her feeding a local cat, the paper reported.
The newspaper described her currently as a "57-year-old yoga instructor and graphic designer."
The Globe story also included many details of Bulger's time on the run, including how Bulger assumed the identity of a local homeless man to obtain medicine and keep a bank account.