Audrey Hale, the 28-year-old assailant who killed six people, three of them 9-year-old students, at a Christian elementary school in Nashville at the end of March, left behind a manifesto, artwork and other writings, according to police.
But the documents have not yet been released, and lawsuits are demanding their public disclosure.
While police have not revealed a motive, Hale studied previous mass shooters, planned and targeted the school and left behind an abundant paper trail, according to authorities. Other killers have left similar documents behind, leaving a grim trail of evidence and potentially also inspiring future murderers.
"When people intent on killing others write manifestos, they want their motivation to be publicized," explained Dr. Katherine Ramsland, professor of forensic psychology at DeSales University. "Sometimes, it's a suicide note, but it can also be an attempt to punish or to inspire others to follow their lead."
Ramsland, the author of "Inside the Minds of Mass Murderers," said such killers typically "vent" against people, institutions or their own social standing.
The National Police Association, media outlets and many members of the public want answers. In part, according to the law enforcement group's attorney, the association is concerned that the work of city police is being interfered with by "outside influences" seeking to keep the manifesto secret.
State law is "simple and straightforward" and the documents must be disclosed unless they fall under an exemption, said Doug Pierce, the lawyer representing the National Police Association and private investigator Clata Brewer in a lawsuit against the City of Nashville and Davidson County.
"It's heartbreaking when you think of it, 9-year-old children gunned down," Pierce told Fox News Digital. "It's very sick, sad and heartbreaking."
Under Tennessee law, documents produced or received by government agencies conducting public business become public records unless they fall into an exempted category. City and county officials have argued that there is an ongoing investigation. However, with the shooter dead, attorneys for the NPA and other groups behind similar lawsuits argue there is no active law enforcement proceeding.
"Rule 16 of Tennessee's rules of criminal procedure, that is a very solid legal basis. We just don’t think that factually it applies here," Pierce said. "The shooter is dead."
Sometimes, after a suspect is killed by police, an investigation could remain open into the officers involved. However, Pierce said that is not what's going on in Nashville.
"Everybody agrees that is not the case," he said. "They acted in a very commendable and heroic fashion, so they're not in trouble."
Earlier this week, the school involved itself in the lawsuit, seeking redactions on some documents, including Hale's hand-drawn maps of the school. While the NPA said it did not oppose the school's motion, a hearing scheduled for Thursday in the case was rescheduled to Monday, May 22, after a group of parents also asked to intervene.
Hale, an artist, had attended the school as a child. The killer had recently begun identifying as a transgender male, according to police, and while the attack is believed to have been planned in advance, the motive remains unclear.
"They want their issue to be noticed," Ramsland told Fox News Digital. "The manifesto gives them the opportunity to feel powerful while they write it as they envision the damage they'll exact against a society that otherwise ignores them."
John Kelly, a criminal profiler who has interviewed numerous serial killers, says it's important to analyze Hale's writings to discern a motive and attempt to halt the next shooting before it happens.
"The manifesto really has to be analyzed to the nth degree," he told Fox News Digital. "Hopefully, it will give us some answers because he is a rare mass murderer, in being declaring himself a male – and we haven’t seen this before."
Hale had recently begun identifying on social media as Aiden Hale, according to authorities.
"He totally believed certain parts of society were the cause of negative events in his life," Kelly said. "I think we'll see this in the manifesto."
Nashville Metro Police Chief John Drake said investigators had not immediately determined a motive but believed that Hale, a former student, had targeted the school and its affiliated church. The killer studied previous mass murders while plotting the attack, he said.
This is another common trait among mass murderers, Ramsland said.
"They study other mission-based killers to learn strategies and avoid mistakes because they seek maximum impact," she told Fox News Digital.
Hale had no prior criminal record but was under a doctor’s care for an unspecified emotional disorder, according to police. In addition to the manifesto they found in Hale's car outside the school, they found self-portraits depicting the same outfit worn during the attack and maps of the school, highlighting points of entry.
In a message sent to a friend the morning of the shooting, the killer warned, "I'm planning to die today," and "You'll probably hear about me on the news."
After searching the suspect’s house, police said they found journals on other school shootings and notes on firearms training. They also recovered two "memoirs" and other evidence that the killer had planned the attack well in advance.
During the plotting, Hale likely dehumanized and objectified the victims, according to Kelly.
"You're talking about the murder of little children and the murder of some adults and whoever else who could’ve been killed," Kelly said. "That was all OK to [Hale], because this is what had to happen to get this manifesto out. … That’s pretty delusional, and [Hale] was a sick individual."
Still, there were "no blatant warning signs," he said.
"Maybe after they release more, we'll say, 'Hey, there's a red flag over there,'" he said. "But I'm not seeing them yet."
According to its website, The Covenant School opened in 2001 as part of Covenant Presbyterian Church and served children from pre-K through sixth grade.
The 9-year-old victims included the pastor's daughter, Hallie Scruggs, and Evelyn Dieckhaus and William Kinney. Police identified the adults as 60-year-old Head of School Katherine Koonce, Cynthia Peak, 61, and Mike Hill, 61.
The shooter brought "significant ammunition" and three weapons to the attack. Within 15 minutes, responding officers killed Hale near a second-story window.