A biology professor charged in the killings of three faculty members at the University of Alabama in Huntsville was initially a suspect in a 1993 attempted mail bombing of a Harvard Medical School professor and killed her brother in 1986 after firing a shotgun 3 times.

Amy Bishop Anderson and her husband, Jim, were questioned after a package containing two pipe bombs was sent to the Newton, Massachusetts, home of Dr. Paul Rosenberg, a Harvard professor and a doctor at Children's Hospital Boston, the Globe said, citing a law enforcement official. At the time, Anderson was working as a postdoctoral fellow in the hospital's human biochemistry lab.

Anderson is charged with capital murder in the Friday shooting deaths, making her eligible for the death penalty in Alabama. Authorities said she was attending a faculty meeting in a university building when she brandished a gun and shot six colleagues, killing three.

The mother of four was arrested as she was leaving the building, Huntsville Police Chief Henry Reyes said Saturday. A 9 mm handgun was recovered from the second floor of the building after the shootings Friday.

On Saturday, it was revealed that in 1986, Anderson, then 19, shot her brother to death in Braintree, Massachusetts. Authorities determined after an investigation that the shooting was accidental.

But Braintree Police Chief Paul Frazier said Saturday, "It is a far different story, I believe, than what was reported back then. I cannot tell you what the thought process was behind our releasing her at the time."

Anderson's husband, Jim, told CNN on Monday that federal investigators had gathered a dozen subjects in the attempted bombing, but "there were never any suspects. Never anyone charged, never anyone arrested."

"Then five years later, we got a letter from the ATF saying, 'You are in the clear,' " he said, referring to the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Sylvia Fluckiger, a lab technician who worked with Anderson at the time, told The Boston Globe on Sunday that Anderson had a dispute with Rosenberg shortly before the bomb incident.

Fluckiger told CNN affiliate WCVB-TV in Boston, "Police interviewed her, and she told me about it. I really wondered if she may have had, you know, some more knowledge, although I'm not accusing her of anything."

Rosenberg was opening a package delivered to his home while he was away on vacation, but he saw wires and a cylinder inside and called police, the Globe reported.

"She was the suspect early on," the law enforcement official, who the Globe said had knowledge of the case, told the newspaper of Anderson. She allegedly was concerned that she was going to receive a negative evaluation from Rosenberg, the official said.

Jim Anderson told The New York Times the December 1986 death of his wife's brother, Seth, was accidental. He declined to comment when CNN asked him about the shooting Monday.

Frazier, however, said Saturday that an official involved in the case and still working for Braintree police told him that the teen had shot her brother during an argument. She fired a shot in her bedroom without hitting anyone, then argued with her brother and shot him, he said.

She fled the home after the shooting and was arrested after pointing a weapon at a vehicle near the house in an unsuccessful attempt to get the driver to stop. During the booking process, then-Chief John Polio called and told the officers to release her, Frazier said. He added her mother was then a member of the Braintree Personnel Board.

Reached by CNN, Polio, now 87 and retired, denied calling in that order, saying detectives told him the shooting appeared accidental and it was determined Anderson should be released to her mother. He said any link between Anderson's release and her mother's position on the board was "laughable."

Anderson's mother, Judith, did not answer her door Monday. Reached by telephone, she told CNN, "We're very distraught," and declined further comment.

A December 8, 1986, article in The Boston Globe said Anderson asked her mother how to unload a round from a 12-gauge shotgun and accidentally shot her brother while she was handling the weapon. The article cited Polio as the source.

The state police report on the incident, released Sunday by the office of Rep. Bill Delahunt, D-Massachusetts, is similar to the Globe's account. Delahunt was district attorney at the time; staffers said he was in the Middle East on Sunday and unable to comment on the case.

The 1986 report said Braintree police told state police investigators "indications were that Amy Bishop had been attempting to manipulate the shotgun and had subsequently brought the gun downstairs in an attempt to gain assistance from her mother in disarming the weapon" when it went off, shooting her brother in the chest.

In a December 17, 1986, interview, Anderson told authorities she "thought it would be a good idea if she learned how to load the shotgun in the house," according to the state police report. The young woman told police she was concerned for her own safety after the family home was broken into, although she previously had been afraid of the gun.

She said she got the gun and loaded shells into it, but was unable to get them out. Anderson said that while she was attempting to unload the weapon on her bed, it went off. She then took it downstairs to ask for help in unloading it, where the shooting occurred.

The police report said both Anderson and her mother said the shooting was accidental. Her mother told police she did not hear the earlier shot in her daughter's bedroom and "believed the house was relatively well soundproofed and that such a discharge would not necessarily be heard on another floor of the house."

Frazier said police records of the incident are missing. But Polio said, "There was no cover-up. Absolutely no cover-up and no missing records. The records were all there when I left. Where they went in the last 22 years and two police chiefs subsequent, I don't know."

Braintree Mayor Joseph Sullivan said Sunday that a review will commence to locate all materials associated with the shooting.

Anderson, who is known to students as Dr. Bishop, had been working at the University of Alabama in Huntsville since 2003 and was up for tenure, according to spokesman Ray Garner. However, authorities wouldn't discuss possible motives or whether the issue of tenure may have played a role in the shooting.

Garner said the university gives teachers six years to get tenure. Those who do not get it are terminated, he said.

Jim Anderson told CNN on Monday that his wife had been denied tenure and had appealed that decision and won, but she was still fighting to be granted tenure. She was frustrated with "the process," he said.

He told CNN earlier his wife had an attorney but would not say who it was, and he described her as a good teacher. He said Monday his wife wrote three novels, "medical thrillers." The couple does not own a gun, he said.

He said he last saw his wife briefly on Friday morning before she left for class. He said she was "loving, got along with everybody."

The family, he said, is devastated, and in "shock, bewilderment, wondering why."

He told the Times the pipe bomb incident is "one thing from the past I hoped would not be dredged up."

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