Maine mass shooter Robert Card who killed 18 in state's worst gun atrocity was suffering from 'profound' brain damage at time experts fear was caused by exposure to blasts at firing range where he worked

Maine mass shooter Robert Card was suffering from traumatic brain injuries when he unleashed a massacre that killed 18 in the state's worst gun tragedy.

The damage was likely caused by recurring exposure to blasts at the Army hand grenade training range where the reservist worked, according to a brain tissue analysis by researchers from Boston University that was released Wednesday.

There was degeneration in the nerve fibers that allow for communication between different areas of the brain, inflammation and small blood vessel injury, according to Dr. Ann McKee of Boston University´s Chronic Traumatic Encephalopathy (CTE) Center. The analysis was released by Card's family. 

'While I cannot say with certainty that these pathological findings underlie Mr. Card´s behavioral changes in the last 10 months of life, based on our previous work, brain injury likely played a role in his symptoms,' McKee said in the statement from the family.

Card's family members also apologized for the attack in the statement, saying they are heartbroken for the victims, survivors and their loved ones.

That soldier, the platoon member said, was ultimately pulled off the grenade training range - where both he and Card, who is pictured above, were almost always stationed

Body camera video of police interviews with reservists before Card's two-week hospitalization in upstate New York last summer also showed fellow reservists expressing worry and alarm about his behavior and weight loss 

Card killed 18 people in a bowling alley and at a restaurant and bar in Lewiston

In November, Louisville Metro police released a report saying they found no evidence Card was suffering from CTE, or chronic traumatic encephalopathy, which is caused by repeated blows to the head.

Card's parents had said they wanted his brain tested for CTE because he had suffered many concussions as a high school athlete. 

Army officials will testify Thursday before a special commission investigating the deadliest mass shooting in Maine history.

The commission is reviewing the facts surrounding the October 25 shootings that killed 18 people in a bowling alley and at a restaurant and bar in Lewiston. The panel, which includes former judges and prosecutors, is also reviewing the police response to the shootings.

Police and the Army were both warned that shooter, Card, was suffering from deteriorating mental health in the months that preceded the shootings.

Some of the 40-year-old Card's relatives warned police that he was displaying paranoid behavior and they were concerned about his access to guns. Body camera video of police interviews with reservists before Card's two-week hospitalization in upstate New York last summer also showed fellow reservists expressing worry and alarm about his behavior and weight loss.

This is the alert every police department in Maine received about Robert Card in September. Two attempts were made to contact him and security was added to the army base, but it was canceled on October 18th

These text messages sent by an Army Reservist Sergeant to his supervisor in September reveal the extent to which there were concerns about Robert Card. The supervisor called police who issued an alert on Card but nothing was done to bring him in or strip him of his weapons

A body is wheeled out on a stretcher at Schemengees Bar and Grille in Lewiston, Maine

Card was hospitalized in July after he shoved a fellow reservist and locked himself in a motel room during training. Later, in September, a fellow reservist told an Army superior he was concerned Card was going to 'snap and do a mass shooting.'

In journal entries Card wrote about wanting to make a difference with the shooting and impact gun laws, mentioning that it was easy for a 'psychopath' like him to buy a firearm. 

The mass shooter was found dead of a self-inflicted gunshot wound after the biggest search in state history. Victims' families, politicians, gun control advocates and others have said in the months since the shootings that law enforcement missed several opportunities to intercede and remove guns from Card. They've also raised questions about the state's mental health system.

Thursday's hearing in Augusta is the seventh and final one currently slated for the commission. Commission chair Daniel Wathen said at a hearing with victims earlier this week that an interim report could be released by April 1.

The 18 victims from the Lewiston mass shooting

Wathen said during the session with victims that the commission's hearings have been critical to unraveling the case.

'This was a great tragedy for you folks, unbelievable,' Wathen said during Monday's hearing. 'But I think has affected everybody in Maine and beyond.'

In previous hearings, law enforcement officials have defended the approach they took with Card in the months before the shootings. Members of the Sagadahoc County Sheriff´s Office testified that the state´s yellow flag law makes it difficult to remove guns from a potentially dangerous person.

Democrats in Maine are looking to make changes to the state's gun laws in the wake of the shootings. Mills wants to change state law to allow law enforcement to go directly to a judge to seek a protective custody warrant to take a dangerous person into custody to remove weapons.

Other Democrats in Maine have proposed a 72-hour waiting period for most gun purchases.