A group of 100 survivors and families of victims killed in the 2023 mass shooting in Lewiston, Maine sued the US government over claims it failed to respond to repeated warning signs that the shooter, an Army reservist, could become violent, according to a lawyer for the group.

The lawsuit, filed in federal court on Wednesday, claims the US Army was negligent in its handling of Army Reserve Sergeant Robert Card, who had exhibited signs of severe mental illness for more than a year before the shooting and made explicit threats to carry out mass violence.

The October 25, 2023, shooting killed 18 people and wounded 13 at a bowling alley and a restaurant. Card was found dead of a self-inflicted gunshot wound two days later.

The lawsuit claims that by March 2023, the US Army knew that Card, a 20-year veteran of the US Army Reserve and a West Point firearm and grenade instructor, was paranoid, delusional, violent and had access to firearms.

But the Army did not remove Card’s guns, dissuaded law enforcement from taking the guns, and dismissed Card’s threats to “shoot up” a Maine Army Reserve center in the month before the massacre, the victims say in the lawsuit.

Representatives for the US Army did not immediately respond to requests for comment.

The lawsuit seeks monetary damages for pain and suffering, for medical and funeral expenses, emotional distress and more.

The lawsuit claims Army researchers have also recognized a connection between service members exposed to repeated explosions, like Card, and increased rates of anxiety, paranoid thinking and aggressive behavior.

Citing other mass shootings committed by veterans and service members, the lawsuit claims the US Army has developed a detailed procedure for dealing with service members whose mental health may make them a threat to themselves or others, but did not follow it in Card's case.

In the months before the Lewiston shooting, members of his unit warned their leadership that Card was making threats about mass shootings and had a collection of firearms.

Card was sent to Keller Army Community Hospital in West Point, New York for an involuntary psychiatric evaluation, where providers found that he had homicidal ideation and was a threat to others.

Despite the findings, Card was discharged, and the US Army did not follow up with him to ensure he was following a treatment plan and was receiving the help he needed, the lawsuit claims.