Authorities were repeatedly warned about the danger Maine gunman Robert Card posed to society in the months before his deadly rampage, authorities have revealed.

Sagadahoc County Sheriff’s Office has revealed Card, a 40-year-old US Army reservist, had managed to avoid detection by police, the FBI, and the government, despite numerous reports raised over a nearly seven-month period about his mental health and weapons skills.

His own family’s concerns about his mental health date back seven months.

Five months before he would conduct the deadliest mass shooting in the US state’s history, Card’s family warned local officials he was hearing voices.

They were also told his mental health was once again rapidly deteriorating.

In July, he spent 14 days in a psychiatric hospital before being released.

The sheriff was advised he was a firearms instructor and had access to weapons.

Nearly three months ago, Card tried and failed to buy a silencer but was thwarted by a local gun shop owner who feared he might pose a danger to others.

But documents made public by the sheriff on Monday revealed repeated attempts to warn authorities fell through the cracks.

As per state documents, a deputy attended his home after a soldier from his reserve unit filed a report that he feared Card was “going to snap and commit a mass shooting” because he was hearing voices again.

The deputy went to Card’s home but could not locate him on numerous attempts.

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 and the like.

Thirty-eight days after his weapons ban, Card opened fire in a busy bar and bowling alley, slaying 18.

He also earned the title of the person behind the 36th mass killing of 2023 in the US.

Card’s body was later found on Friday after a tense, two-day manhunt.

And, despite all the complaints raised about him, Card was found with a cache of weapons at a premises in the nearby town of Lisbon Falls.

Authorities believe they were all legally purchased.

Maine governor Janet Mills confirmed to the press on Monday that legislators will revisit state gun laws in response to the shootings and numerous instances of falling through the cracks of the current legislature.

Police are still refusing to confirm if Card’s mass slaying on Wednesday was a planned attack.