BOSTON (CBS/AP) Amy Bishop, a former biology professor at the University of Alabama, already faces murder charges in two states - for the shooting rampage that killed three colleagues in February, and for the 1986 shooting death of her brother, Seth. However, she won't be facing charges for a 1993 mail bomb incident in Boston, federal prosecutors announced Thursday.
Bishop was questioned in 1993, along with her husband, James Anderson, after a Harvard Medical School professor who gave her a poor performance review received two pipe bombs in the mail. The bombs did not go off.
During the investigation, the targeted professor, Dr. Paul Rosenberg, told investigators that Bishop had resigned her job as a post-doctorate research fellow with him around the time he was mailed the pipe bomb.
Rosenberg said that "he had been instrumental in her leaving because he had felt she could not meet the standards required for the work," according to a report by the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives.
Additional witnesses told investigators that Bishop's husband said "he wanted to get back at Dr. Rosenberg and that he wanted to shoot him, bomb him, stab him or strangle Rosenberg," according to the report.
However, the ATF was never able to trace the origin of the bombs, and after questioning Bishop and her husband, "were unable to gather sufficient evidence to bring charges," U.S. Attorney Carmen Ortiz said in a statement Thursday. "As a result, the matter was closed."
Ortiz said her office decided to review the investigation after Bishop was charged with the Huntsville, Alabama shootings. Bishop's Alabama attorney, Roy Miller, said he was unaware that authorities in Massachusetts had been reviewing the mail-bombing.
"But I'm glad to hear it was cleared up favorably," he said.
Bishop is charged with capital murder and attempted murder in the Alabama shootings, which killed three colleagues and wounded three others. After the killings, stories of violence in Bishop's past surfaced, prompting Massachusetts authorities to reopen the investigation into the death of her brother in 1986 which was originally labeled an accident.
In June, a grand jury indicted Bishop for murder in that case. In 1986, Bishop told police she accidentally shot her brother Seth in the family's Braintree, Ma. home while trying to unload her father's shotgun.