(CNN) -- It's no secret in Braintree, Massachusetts, that Amy Bishop killed her younger brother with a single shotgun blast to the chest in her parents' kitchen more than 20 years ago.
And so, when Bishop allegedly shot six of her colleagues, killing three, at the University of Alabama at Hunstville in February, new questions surfaced about her brother's shooting death.
After the December 1986 shooting death of Seth Bishop, Braintree police collected evidence from the scene, questioned the then 20-year-old Bishop and her parents and determined that the shooting was an accident.
This week, a judge will re-examine Seth Bishop's death in light of information from newly discovered police reports.
The closed-door hearing, known as an inquest, begins Tuesday. Under Massachusetts law, inquests are invoked in cases of suspicious deaths so a judge can gather facts to determine the "material circumstances attending the death" and whether an "unlawful act or negligence" of someone else contributed to it.
At the conclusion of the inquest, the judge will write a report of his findings that the district attorney can present to a grand jury.
Norfolk County District Attorney William Keating ordered the inquest about two weeks after former biology professor Amy Bishop was arrested in the February 11 shooting deaths of three colleagues during a faculty meeting at the University of Alabama in Huntsville.
A gag order has been issued in the Alabama murder case, and Bishop's attorneys did not return CNN's calls for comment.
The triple slaying prompted authorities in Braintree to locate missing investigative reports related to Seth Bishop's death in 1986, which was ruled at the time to be an accident.
Authorities decided then not to press charges against Amy Bishop, who told police that she accidentally shot her brother in front of her mother while she was attempting to unload a 12-gauge pump-action shotgun in the kitchen.
But the incident has haunted the community ever since, with current members of the police force now acknowledging that the decision to let Bishop off did not go over well.
"I was not on duty at the time, but I recall how frustrated the members of the department were over the release of Ms. Bishop," Braintree Police Lt. Karen MacAleese said in a statement in February.
"It was a difficult time for the department as there had been three shootings within a short time frame," she added. "The release of Ms. Bishop did not sit well with the police officers and I can assure you that this would not happen in this day and age."
A state police report filed in March 1987 said that interviews with Judy Bishop -- Amy and Seth Bishop's mother and the sole witness to the shooting -- supported her daughter's claim that the gun discharged accidentally. The report concluded that "no further investigation into the death of Seth Bishop was warranted."
But interviews with witnesses and the Bishop family, included in the 36 pages of documents released in February, added context to the day in question, casting Amy Bishop's behavior that day as sometimes erratic.
Amy Bishop told police that there had been a family "spat" earlier in the day, according to police reports. Later on, she told police, she was in her room trying to load her father's shotgun, because she was concerned about robbers, and accidentally fired a round into her wall. Investigators later found the hole and the spent shell in the room, the report notes.
Amy Bishop said she then went downstairs to seek her brother's assistance and accidentally shot him. She said she fled the house in a panic, according to the reports, wearing her jacket and carrying the gun.
After she left the house, two employees told police that a girl with a shotgun entered a nearby auto body shop.
"She pointed the gun at them and said she wanted a car and a set of keys right away," the officer wrote. "She told them to step back while keeping the gun on them. As they stepped back she went outside and headed up toward Wash. St."
When she was arrested less than two hours later near Braintree Square, with the gun in her possession, one officer said she appeared "confused" and "disoriented."
When police tried to question Amy Bishop a few weeks later, she said there was much about the incident she couldn't remember but insisted the shooting had been accidental. She also said she was having a difficult time dealing with what had occurred, and was taking medication.
A review of the police reports indicated that probable cause existed at the time to charge Bishop with assault with a dangerous weapon, carrying a dangerous weapon, and unlawful possession of ammunition, the district attorney's office said last month.
The statute of limitations has expired on those charges and on the charge of involuntary manslaughter, district attorney's spokesman David Traub said.
However, if Quincy District Court Judge Mark Coven finds evidence to support a charge of first-degree or second-degree murder, he could recommend the charges in a report that the district attorney can present to a grand jury -- the only mechanism through which Bishop can be indicted, he said.
Amy Bishop's explanation may have been enough for police at the time, but to many in Braintree, it raised more questions than it answered.
"What was the argument about? Why did she have her coat on if she went downstairs not planning to leave? How, if she accidentally blew a hole through the wall, did she come downstairs with the gun reloaded? Why doesn't the state police report say she pointed a gun at the mechanic?" Traub said, ticking off the most commonly asked questions.
"This is a death that occurred in 1986 for which there was no prosecution and the community is now looking at the investigation and wondering why fundamental questions weren't answered," he said.
Bishop, who remains in custody in the Alabama case, is permitted under Massachusetts law to attend the inquest, but is not required to appear.