https://www.bbc.co.uk/news/world-us-canada-67263059
Three months before a US Army reservist fatally shot 18 people in Maine, the military says it determined he should not be allowed a weapon.
Robert Card was evaluated in July after behaving erratically and was found to be "non-deployable due to concerns over his well-being", the Army said.
He spent 14 days in a psychiatric hospital before being released.
Card was found dead on Friday, ending a manhunt after the mass shooting at a bar and bowling alley last Wednesday.
More than a dozen people were also injured in the shooting in the city of Lewiston.
Maine firearms store owner Rick LaChapelle told the New York Times and ABC News the 40-year-old suspect had entered his shop on 5 August to pick-up a silencer he had bought online.
He had to fill out a form, which included a question that asked: "Have you ever been committed to a mental institution?"
Card answered yes, Mr LaChapelle said.
The staff looked at the form and told Card he was not eligible to purchase the silencer because of his answers on the questionnaire.
Card was committed to a mental health facility for two weeks in July after "hearing voices and threats to shoot up" a military base, the Associated Press reported.
That same month, the military decided that Card was "non-deployable due to concerns over his well-being", Army spokesperson Lt Col Ruth Castro said in an emailed statement.
Card was also deemed unfit by the Army to have a weapon, handle ammunition or "participate in live fire activity". They said the Army Reserve Command had made "multiple attempts" to contact Card.
Police have confirmed that Card was known to have undergone mental health evaluations, but that he had never been forcibly committed for treatment.
In September, the Maine National Guard issued a state-wide warning about Card, saying that they feared he would "snap and commit a mass shooting", according to law enforcement sources who
spoke to CNN.
The warning came after another incident in which Card allegedly punched his friend - a fellow soldier - during an argument and made threats against his US Army base in Saco, Maine.
Sagadahoc County Sheriff Joel Merry said in a Monday evening statement that his office was contacted in May by members of Card's family concerned over his mental health and access to weapons.
Mr Merry said a deputy within his office notified the reservist's Army Reserve training group.
The sheriff said that on two occasions in September a deputy could not find the reservist at his home in Bowdoin, prompting the state-wide alert.
The litany of missed warnings on Card have sparked a debate about Maine's "yellow flag" law, passed in 2019.
The measure requires several steps before guns can be taken by authorities from someone deemed to pose a danger to himself or others.
It is seen as a weaker version of a "red flag" law, which involve fewer procedural steps in allowing a court to order the temporary removal of a firearm from someone.
Card was found dead from an apparently self-inflicted gunshot wound on Friday night, police said, near a river around 10 miles (16km) from Lewiston.