His decades-long obsession with a college sorority may link a former Army biowarfare scientist to four anthrax-laced letters dropped off at a New Jersey mailbox in 2001, authorities said Monday in the latest twist of one of the most bizarre unsolved crimes in FBI history. People walk by a brick office building 20 Nassau St., in Princeton, N.J., Monday, Aug. 4, 2008. A sorority, Kappa Kappa Gamma, has an office in this building. Former Army scientist Bruce Ivins, the top suspect in the 2001 anthrax attacks was obsessed with a sorority that sat less than 100 yards away from a New Jersey mailbox where the toxin-laced letters were sent, authorities said Monday. A hazardous materials unit worker is hosed down on Capitol Hill in this Tuesday, Oct. 23, 2001 file photo where worked continued inspecting buildings and offices for anthrax contamination. A top U.S. biodefense researcher, Bruce E. Ivins, 62, apparently committed suicide just as the Justice Department was about to file criminal charges against him in the anthrax mailings that traumatized the nation in the weeks following the Sept. 11, 2001, terrorist attacks, the Los Angeles Times reported in their Friday Aug. 1, 2008 editions. Frederick Police wait on the porch at the home of Bruce E. Ivins, 62, who died Tuesday of an apparent overdose of prescription Tylenol mixed with codeine, Friday, Aug. 1, 2008, in Frederick, Md. Ivins, a top U.S. biodefense researcher who, according to his brother, was being aggressively pursued by the FBI in connection with a series of anthrax mailings after the Sept. 11, 2001 terrorist attacks apparently committed suicide. Bruce E. Ivins, a biodefense researcher is seen in 2003, at Fort Detrick, Md. Ivins, the scientist who was developing a vaccine to combat anthrax, died Tuesday July 29, 2008, in an apparent suicide in a hospital in in Frederick, Md. U.S. prosecutors investigating the 2001 anthrax attacks were planning to indict and seek the death penalty for Ivins in connection with mailings of the deadly anthrax toxin that killed five people.