Maine’s congressional delegation is ramping up pressure on the U.S. Army to explain its apparent failure to address the danger posed by a reservist with known mental health issues and a history of making violent threats before he killed 18 people and injured 13 others during an October shooting rampage at two locations in Lewiston.

Robert Card was experiencing a mental health crisis in the months leading up to the deadliest shooting in state history, saying he heard voices and believed that local businesses and others were broadcasting that he was a pedophile.

Sens. Angus King and Susan Collins, top, and Reps. Chellie Pingree and Jared Golden, bottom.

Card repeatedly made threats, including a specific threat to shoot up an Army Reserve training facility in Saco, and spent time in a New York psychiatric hospital, but authorities did not take steps to remove his access to firearms under New York or Maine laws specifically designed for such cases.

In a letter Friday to Lt. Gen. Donna W. Martin, the Army’s inspector general, Sens. Susan Collins and Angus King, and Reps. Chellie Pingree and Jared Golden called on Martin to conduct a comprehensive investigation in addition to an ongoing administrative review.

“This tragedy warrants a much broader, independent inquiry,” the delegation wrote in the letter. “We must work to fully understand what happened – and what could have been done differently that might have prevented the Lewiston shooting – on the local, state and federal levels. We must also give the American people confidence that the investigation is comprehensive and unbiased.”

Collins noted that Card’s reserve unit restricted his access to Army-issued weapons and prohibited him from participating in live-fire drills because they were concerned. But they never sought to seize his private firearms or prohibit him from buying new ones.

“When I started reading all of the reports on Robert Card, what struck me was the number of warning signs,” Collins said during an appearance on WVOM radio Friday. “It didn’t seem to be a close call. He threatened to shoot up the Army’s facility in Saco. He punched a fellow Army reservist when he was in New York on a drill exercise. He made threats and he expressed violence towards others.”

The letter comes a day after the delegation members met with grieving relatives of shooting victims. The families traveled to Washington this week to tell lawmakers about their loved ones, demand answers about the missed warning signs and, in some cases, call for new gun safety legislation, particularly around assault weapons such as the rifle used in the Lewiston shootings.

It’s the second letter from members of the delegation. Collins and King sent a letter on Nov. 6 to the inspector general with a series of questions about how the Army handled Card, whose behavior during a training mission in New York was so concerning that he voluntarily spent two weeks at a psychiatric hospital.

The senators received a response a week later, saying an administrative review was underway and that it would “likely take time to complete.”

Gov. Janet Mills and Attorney General Aaron Frey recently formed an independent commission to examine the events leading up to the Oct. 25 shooting and the police response.

On Oct. 25, Card entered two businesses in Lewiston, where he fatally shot 18 people and wounded 13 others in one of the deadliest mass shootings in U.S. history. The massacre led to a tense 48-hour manhunt before police found his body in a trailer in Lisbon, where he took his own life.

The 40-year-old Bowdoin man was acting erratically for months and spent two weeks at a New York psychiatric hospital last summer following an incident with fellow reservists. Family members and friends in the Army unit expressed concerns about Card as recently as mid-September. One reservist even texted another to say he feared Card might snap and “do a mass shooting.”

Both New York and Maine have laws that allow authorities to temporarily confiscate weapons from people who are deemed a danger to others or themselves, but nobody in either state initiated those laws in response to Card’s actions and threats.

The shooting has prompted calls for more gun safety legislation in Maine and nationally.