The family and colleagues of a US army reservist who shot dead 18 people in a gun rampage in a bowling alley had warned the authorities over his mental health before his killing spree.
Robert Card, 40, was found dead three days after launching his deadly attack on Wednesday.
In July, he spent 14 days in a psychiatric hospital after his family and fellow army reservists had expressed fears over his mental state.
He was released but concerns were again raised by his colleagues.
Maine police were warned by one that Card would “snap and commit a mass shooting” less than six weeks before he allegedly went on his violent rampage.
The Maine National Guard asked local police to conduct a welfare check on Card in September after he made threats against his US army base, according to CNN.
Eventually, a statewide alert was issued to warn authorities that he was known to be “armed and dangerous”.
His army reserve unit then restricted weapons access and declared him “non-deployable”, barring him from checking out firearms, weaponry or ammunition.
Thirty-eight days after his weapons ban, Card opened fire in a busy bar and bowling alley.
He was found dead from an apparently self-inflicted gunshot wound following a huge police manhunt, Maine Commissioner of Public Safety Michael Sauschuck said.
Three others injured in the shooting are in a critical condition.
Card's body was found on Saturday in a cargo trailer in Lisbon near where the shooting occurred.
Officials said a note addressed to Card's son was found at a home associated with the suspect on Thursday. His mobile phone and a gun were also found in a white Subaru that was identified as belonging to him.
The manhunt included 80 FBI agents and Coast Guard personnel and the area around the murder scene was put on lockdown.
Card was accused of killing 18 people and injuring 13 as he sprayed bullets with a semi automatic weapon around the Just-In-Time Recreation bowling alley in Lewiston. A father of four and a 14 year-old boy were among the victims.
