Former FBI special agent Nicole Parker breaks down the warning signs ahead of the Maine shooting on 'Your World.' The Army reservist who killed 18 people in what became Maine's deadliest mass shooting in the state's history, sparking a massive manhunt before he was found dead last year, had traumatic brain injuries, a news scan shows.

According to a brain tissue analysis conducted by researchers from Boston University and released by Card's family, Robert Card, the perpetrator of the shooting, had significant evidence of traumatic brain injuries. The analysis, conducted by Dr. Ann McKee of Boston University's Chronic Traumatic Encephalopathy (CTE) Center, revealed degeneration in the nerve fibers responsible for communication between different areas of the brain, inflammation, and small blood vessel injuries.

Card had been an instructor at an Army hand grenade training range, where it is believed he was exposed to thousands of low-level blasts. The brain analysis showed evidence of degeneration, axonal and myelin loss, inflammation, and small blood vessel injuries in the white matter of the brain. However, no evidence of chronic traumatic encephalopathy (CTE) was found.

Dr. McKee stated, "These findings align with our previous studies on the effects of blast injury in humans and experimental models. 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."

In a statement released through the Concussion Legacy Foundation, Card's family apologized for his actions and expressed their deepest sympathy for the victims, survivors, and their loved ones. They also thanked Dr. McKee for her assistance in understanding Card's brain damage and how it may have impacted his mental health and behavior.

The family hopes that by releasing these findings, more awareness of traumatic brain injury among military service members will be raised. They also called for further research and support for military personnel with traumatic brain injuries.

The Maine Chief Medical Examiner's office also received appreciation from the family for requesting the brain analysis. The commission established by Democratic Gov. Janet Mills, composed of former judges and prosecutors, will review the facts surrounding the shootings and the police response. Both the police and the Army were warned about Card's deteriorating mental health in the months leading up to the shootings.

Fellow reservists had expressed concerns about Card's behavior, including paranoid behavior, access to guns, and weight loss. Body camera footage revealed interviews before Card's hospitalization, wherein fellow reservists voiced their worries and alarm. Card was eventually found dead from a self-inflicted gunshot wound after an extensive search.

The seventh and final hearing of the commission is scheduled for today in Augusta. Commission chair Daniel Wathen mentioned the possibility of an interim report being released by April 1. In response to the shootings, Democrats in Maine are pushing for changes to the state's gun laws.