A newly-released autopsy reveals very severe brain damage in the frontal lobe of former NFL player Phillip Adams, who is accused of fatally shooting six people in Rock Hill, S.C., before committing suicide.

According to the Associated Press, on Tuesday (December 14), authorities announced the autopsy results completed by Dr. Ann McKee who concluded that the 32-year-old had stage 2 chronic traumatic encephalopathy which his 20 years of playing football “gave rise” to.

Adams’ degenerative disease, known as CTE, is linked to head trauma and concussions that can lead to a range of symptoms, including violent mood swings and memory loss.

“There were inklings that he was developing clear behavioral and cognitive issues,” McKee said, according to the AP. “I don’t think he snapped. It appeared to be a cumulative progressive impairment. He was getting increasingly paranoid, he was having increasing difficulties with his memory, and he was very likely having more and more impulsive behaviors. ... It may not have been recognized, but I doubt that this was entirely out of the blue.”

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On April 7, authorities say Adams killed Rock Hill physician Robert Lesslie; his wife, Barbara; two of their grandchildren, 9-year-old Adah Lesslie and 5-year-old Noah Lesslie; and two HVAC technicians working at the Lesslie home, as well as James Lewis and Robert Shook, both 38. Adams was later discovered by police with a self-inflicted gunshot wound to his head. Rock Hill is a suburb of Charlotte, N.C., about 25 minutes outside of the city.

While of the 24 NFL players diagnosed with CTE by the CTE Center at Boston University after dying in their 20s and 30s had stage 2 like Adams, Lesslie says his case was “unusually severe” in both frontal lobes.

McKee compared Adams’ brain to that of Aaron Hernandez, the former football star who also was posthumously diagnoesed with CTE after he hanged himself in prison while serving a life sentence for murder.

McKee says that a combination of the abnormalities caused by frontal lobe damage could theoretically lower someone’s threshold for homicidal acts, however it’s difficult to attribute homicidal behavior to CTE alone because “it’s a complicated issue with many other factors.”

Adams’ family said they were not surprised that he had the disease, but were shocked to learn how severe his condition was.

“After going through medical records from his football career, we do know that he was desperately seeking help from the NFL but was denied all claims due to his inability to remember things and to handle seemingly simple tasks, such as traveling hours away to see doctors and going through extensive evaluations,” their statement said, according to the AP.

Adams played in 78 NFL games for six teams over six seasons, including the San Francisco 49ers, New England Patriots, Seattle Seahawks, Oakland Raiders, New York Jets and Atlanta Falcons.