Alleged Maine mass shooter's brain being studied for CTE linked to military service

The brain of the alleged Maine mass shooter is being studied to determine whether his reported mental health problems could be linked to brain damage sustained during his military service, a spokesperson for Maine's Office of the Chief Medical Examiner confirms to ABC News.

Samples from alleged gunman Robert Card's brain have been sent for additional testing to Boston University, the spokesperson said, which has the nation's largest brain bank focused on studying chronic traumatic encephalopathy, or CTE.

The state's chief medical examiner wants CTE testing done on Card's brain "due to the combined history" of his "military experience and actions," the spokesperson, Lindsey Chasteen said.

They are hoping to understand whether blast exposure during hand grenade training could have taken a toll on Card's brain -- and mental state.

"The reason further testing is being conducted on Mr. Card’s brain is that in an event such as this, people are left with more questions than answers," Chasteen said. "It is our belief that if we can conduct testing (in-house or outsourced) that may shed light on some of those answers, we have a responsibility to do that."

It could take six to eight months for results of Card's brain testing to come back, Chasteen said.

The news of the testing on Card's brain was first reported by the New York Times.

Card, a 40-year-old Army Reservist, had a well-documented series of warning signs that his psychological state was on a sharp decline in the months leading up to the Oct. 25 shootings, when he allegedly opened fire at a bar and bowling alley in Lewiston, claiming 18 lives and injuring 13 more.

After a two-day manhunt that forced thousands to shelter in place, police found Card dead of a self-inflicted gunshot wound at the recycling center where he once worked.

Leading up to the shootings, Card's own immediate family, fellow soldiers and other community members had already warned police they worried that he might "snap," that he had been hearing voices and making violent threats.

Last July, Card was institutionalized for two weeks for psychological treatment and evaluation during a stay at West Point in New York, after it became clear to his fellow soldiers who reported that Card's mental state appeared to be deteriorating. He was released after 14 days, authorities said.

Following Card's hospitalization, the Army said it directed Card’s commander that he "should not have a weapon, handle ammunition and not participate in live fire activity," and directed that Card "should not be put in a deployable status "due to concerns over his well-being" and that the Army Reserve’s surgeon’s office and Army Reserve’s medical management team "made multiple attempts" to contact Card.

A spokesperson for Boston University declined to comment on analysis of Card's brain, saying "it is the policy of the CTE Center that we cannot and do not discuss any current, past or potential cases without written consent of next of kin."

Growing attention has been paid to traumatic brain injury and CTE due to rising awareness of the repeated blows sustained by professional football players -- and the lasting, damaging impacts that may ripple from them.

Soldiers and professional athletes are among the groups at highest risk for CTE, experts say.

There’s some evidence that exposure to blasts can affect the brain, but research is still evolving, experts say. It’s possible that they can cause similar damage to a traumatic brain injury caused by physical impact, though the specific way that happens remains unclear, and each traumatic brain injury is unique. Experts say there is some evidence that people who suffer traumatic brain injuries have some changes in behavior and mood, and that they may have higher levels of aggressive behavior.

Card was an Army Reserve Sgt. 1st Class, and a known capable marksman.

In raising concerns about his mental state to police in May, Card's ex-wife described his role with the Army Reserve as having "historically instructed soldier[s] on the use of hand grenades," according to an incident report previously obtained by ABC News.

His immediate family members raised concerns to police in May that Card had begun to exhibit paranoid delusions and claimed people were saying "derogatory" things about him while out in public and that he was growing increasingly "angry and paranoid" through the spring.

Card had already started wearing hearing aides by last February, which was when his brother began to notice Card's paranoia and anger starting, according to the May police incident report.

In mid-September, Card's training supervisor would be moved to write a worried letter to local law enforcement requesting a welfare check on Card, who he refers to as one of his senior firearms instructors, noting that Card had been "hearing voices" and it had "only gotten worse," according to another incident report.

Authorities now seek to understand whether his deterioration could have been linked to potential brain damage from his time with the Army Reserve handling grenades.

Card was an Army Reservist since December 2002, the Army said. His job was a Petroleum Supply Specialist and he had no combat deployments.

The Army said it is conducting its own internal investigation into Card.