Families of the individuals affected by a 2023 mass shooting in Maine, along with many survivors, are set to pursue a negligence lawsuit against the U.S. government on Wednesday. They claim that the military and others did not adequately address warning signs and threats posed by the shooter, who was an Army reservist.

Robert Card, aged 40, was responsible for the deaths of 18 people at a bowling alley and a bar in Lewiston, which prompted a massive two-day search that concluded with his suicide, as reported by authorities.

Around 100 plaintiffs plan to include the Defense Department, the Army, and Keller Army Community Hospital in West Point, New York, in their lawsuit. This legal action is to be filed by a coalition of four law firms in the federal court in Maine.

Maine lawyer Travis Brennan stated, “The Army repeatedly failed to uphold its duty to protect the community it vowed to defend and should be held accountable.”

Another attorney in Maine advocating for the plaintiffs, Benjamin Gideon, mentioned, “It’s difficult to envision the Army taking responsibility without being compelled in court.”

In October, the law firms issued legal notices about their intent to sue. The attorneys argue that the Army had several chances to address Card’s situation but failed, starting as early as May 2023, when his son expressed concerns about Card’s worsening mental health and erratic behavior.

The Justice and Defense departments and the Army could not immediately be reached for comment about the planned complaints. They previously declined to comment on the legal notices.

National Trial Law, a law firm in Texas, is working with two Maine law firms to represent the plaintiffs. The firm represented survivors and families of those killed in the 2017 church shooting in Sutherland Springs, Texas, committed by an Air Force service member. The federal government was found partly liable in that case, and the survivors agreed to settle in 2023 after the Justice Department appealed.

The legal cases in Maine are similarly focused on the federal government and actions taken by military members.

Despite the apparent warning signs, a definitive motive for the rampage in Lewiston remains unclear. Card’s family has said that he claimed to have been hearing voices months before when he was fitted for high-powered hearing aids and that he had grown increasingly paranoid.

A month after the shootings, an independent commission was formed to investigate it and scrutinize any lapses by the military, law enforcement and Card’s family.

The commission’s report and the military investigations shed light on possible failures.

The military’s internal report said Card’s unit failed to follow certain procedures after he was involved in a shoving incident with another reservist in July 2023, leading him to be hospitalized for two weeks in a psychiatric unit at a civilian hospital. At the time, his reported symptoms included psychosis and homicidal ideations, and he had created a “hit list,” according to the military’s investigation.

The Army then prohibited Card from having access to weapons on duty.

A separate independent report by the state commission concluded that while the gunman was solely responsible for his conduct, there were missteps. Leaders of Card’s unit “failed to undertake necessary steps to reduce the threat he posed to the public,” such as ignoring “strong recommendations” from his mental health providers to stay engaged with his care and ensure any weapons in his home were removed.

The commission also found that his unit “neglected to share” all the information it had about past threats with the local sheriff’s office.

In addition, the commission said, medical staff members at Keller Army Community Hospital, where Card was initially evaluated three months before the shootings, failed to file a so-called SAFE Act notice. The report is used to alert authorities when people may be dangers to themselves or others.

The military and independent commission reports also detailed how Card’s family alerted a Sagadahoc County sheriff’s sergeant about his deteriorating mental health. The report further said that law enforcement agencies had probable cause to initiate Maine’s “yellow flag” law, which allows them to confiscate people’s firearms if they are believed to be threats to themselves or others, but that that was never done.

Sagadahoc County Sheriff Joel Merry said after the shootings that the Army Reserve did inform his department that Card threatened to “shoot up” the National Guard base in Saco, Maine. Merry said he distributed a statewide alert to law enforcement agencies after deputies sent to Card’s home in Bowdoin could not find him.

Investigators also looked at whether Card’s exposure to low-level blasts as a hand grenade instructor in the military was tied to the “severe” traumatic brain injury that researchers found evidence of last year. The military denied in its report that any brain-related injury was linked to his service.

The law firms had previously said they were focusing on the federal government and not local law enforcement because the Army had access to the most critical information about Card’s state of mind and could have helped ensure he did not have access to firearms.

Card’s unit failed to conduct a required “line of duty investigation,” which would have documented the condition of his mental state, the Army acknowledged in its internal report.

Card’s family told NBC News a year after the shootings that they supported further research of military service members’ brains. They also launched a nonprofit organization, Rising Over Brokenness, to focus on mental health awareness and brain injuries among service members.

If you or someone you know is in crisis, call or text 988 or go to 988lifeline.org, to reach the Suicide & Crisis Lifeline. You can also call the network, previously known as the National Suicide Prevention Lifeline, at 800-273-8255 or visit SpeakingOfSuicide.com/resources.