HUNTSVILLE, Ala.—On Friday, this city of rocket scientists and brainy inventors was stunned when a neuroscientist with a Harvard Ph.D. was arrested in the shooting deaths of three of her colleagues after she was denied tenure.

But that was only the first surprise in the tale of the neuroscientist, Amy Bishop, who was regarded as fiercely intelligent and had seemed to have a promising career in biotechnology. Every day since has produced a new revelation from Bishop's past, each more bizarre than the last.

On Saturday, the police in Braintree, Mass., said that she had fatally shot her brother in 1986 and questioned whether the decision to dismiss the case as an accident had been the right one.

On Sunday, a law enforcement official in Boston said she and her husband, James Anderson, had been questioned in a 1993 case in which a pipe bomb was sent to a colleague of Bishop's at Children's Hospital Boston.

The bomb did not go off, no one was ever charged in the case, and no proof ever emerged connecting the couple to the bomb plot.

On Sunday, Anderson firmly defended his wife in an interview at their home in Huntsville, saying that she had been completely cleared in the pipe bomb case and that her brother's death had been accidental.

“;That's incorrect,”; he said about reports linking him and his wife to the bomb plot. “;We were not suspects. They questioned everybody that ever knew this guy.”;

The target of the mail bomb was Dr. Paul Rosenberg, according to The Boston Globe, which first reported that the couple had been questioned in the case. After returning home from a vacation, Rosenberg opened a package that contained two 6-inch pipe bombs connected to two nine-volt batteries, The Globe reported. The doctor and his wife fled and called the police.

Officials said that Bishop was concerned that Rosenberg would give her a negative evaluation on her doctorate work, the newspaper wrote, and that they were concerned about the incident involving her brother. The authorities in Boston searched Bishop's computer at the time and found a novel she was working on about a scientist who killed her brother and atoned by excelling at her work, The Globe reported.

Though he firmly protested his wife's innocence in the earlier cases, Anderson said he remained mystified over Friday's shootings, which left three professors dead and three other people wounded after a faculty meeting at the University of Alabama, Huntsville.

Bishop was charged with capital murder; three charges of attempted murder were added on Sunday. Anderson said he did not know of any specific incident that could have led to the shooting, and did not know that his wife allegedly had a gun when she went to the meeting.

“;I had no idea,”; he said. “;We don't own one.”;

Those killed were Gopi Podila, 52, the chairman of the biology department; Maria Ragland Davis, 50, a professor who studied plant pathogens; and Adriel Johnson, 52, a cell biologist who also taught Boy Scouts about science.

Two of the wounded were Joseph Leahy, 50, a microbiologist, and Stephanie Monticciolo, 62, a staff assistant, both of whom were in critical condition. The third was Luis Cruz-Vera, 40, a molecular biologist, who was released from the hospital on Saturday.

Anderson said that months ago, the university administration overruled a successful appeal of the decision to deny Bishop tenure in spring 2009.

“;She won her appeal,”; he said, “;and the provost canned it.”;

The university has declined to elaborate on the details of Bishop's tenure application, saying only that she was denied last spring and that she could stay at the university only until the end of this academic year. Even if a faculty member successfully appeals a tenure denial, the final decision rests with the administration.

But Bishop had continued to fight, appealing to two members of the University of Alabama System's Board of Trustees for help and hiring a lawyer, who was “;finding one problem after another with the process,”; Anderson said. One issue was a dispute over whether two of her papers had been published in time to count toward tenure, he said.

“;She exceeded the qualifications for tenure,”; Anderson said. “;The review board said, 'Grant it or go through the process again.”;'

Anderson said that his wife's research was generating millions of dollars for the university, that she had published numerous papers and that she was a good teacher.

But that estimate of her financial benefit to the university seems likely to be premature. One of her innovations, an automated system for producing cell cultures that the couple developed together, has attracted $1.25 million in financing but has not yet reached the market. Another, a potential treatment for degenerative diseases like Alzheimer's, is in the process of being licensed from the university. Typically, universities share the proceeds from such licenses with the scientists responsible.

The police said Saturday that Bishop was 45, but her birth date on a university Web site indicated that she was 44.

Anderson said he could not gain access to his wife's e-mail account and did not know if she had received any news that might have set off the shooting. The police, he said, had taken a thick binder documenting her tenure battle, her computer and the family van. At least one of the trustees had recently told her that he could not help reverse the tenure decision, a family friend said.

Anderson said he had already told the Huntsville police that they might come across the Boston pipe bomb incident during their investigation.

Sylvia Fluckiger, who worked as a laboratory technician at Children's Hospital when Bishop and Rosenberg were working there, said Bishop had acknowledged that she was questioned by the police about the pipe bomb incident.

“;She was visited by the police,”; Fluckiger said. “;What she said is they asked her if she had ever used a stamp, taken it off an envelope and put it somewhere else.”;

Fluckiger said Bishop “;had a smirk on her face”; when asked about the incident. “;I don't know why she was smirking,”; she said. “;It was a funny expression on her face.”;

“;We did know that there was a dispute between Paul Rosenberg and her,”; Fluckiger said, adding that she could not recall the details.

On Saturday, the police in Braintree said they were considering reopening the case of the shooting death of her brother, Seth Bishop, 18. Although a state police report said investigators determined that the shooting was an accident, Police Chief Paul Frazier said other officers remember that it came after an argument and questioned why local police documents could not be found.

On Sunday, Mayor Joseph C. Sullivan of Braintree, a Boston suburb, issued a statement saying the town would conduct a “;full and thorough review”; of its records for any material relating to Seth Bishop's death. But he noted that records from 1986 were created and maintained manually, which would complicate their retrieval.

Standing at his door after church on Sunday, Anderson confirmed the existence of the novel reported in The Globe, as well as two others his wife worked on in her spare time. The couple has four children, ranging from grade-school to college age. Anderson said that somewhere in his files he had a letter sent by the Bureau of Alcohol, Tobacco and Firearms after the bomb investigation, saying: “;You are hereby cleared in this incident. You are no longer a subject of the investigation.”;

“;This is one thing from the past I hoped would not be dredged up,”; he said.