Studying Hernandez's brain (pictured right) after his death, investigators found his CTE was advanced. Photo / Netflix
Studying Hernandez's brain (pictured right) after his death, investigators found his CTE was advanced. Photo / Netflix
When Aaron Hernandez's lawyer announced his brain would be donated to science just days after his death, it was dismissed by some as just a bizarre publicity stunt.
In 2017, the former NFL player took his own life just days after being acquitted of a double murder, which Hernandez had stood trial for while serving a life sentence for the murder of Odin Lloyd, the boyfriend of his fiancee's sister.
At the time, Hernandez had been a promising young player for the New England Patriots who had a US$58 million contract with the team after being drafted at just 20.
However, his life was also marred by reports of erratic and violent behaviour, with Hernandez suspected of involvement in another slaying that he never stood trial for.
But now, almost three years on, the decision to donate Hernandez's brain is providing some possible answers as to why the troubled young athlete became increasingly violent before taking his own life.
Hernandez's brain was found to have one of the worst cases of chronic traumatic encephalopathy (CTE), a degenerative brain disease caused by repeated head injuries.
Former New England Patriots tight end Aaron Hernandez. Photo / Getty
How this could have impacted Hernandez's life is examined in a new three-part Netflix documentary, Killer Inside: The Mind of Aaron Hernandez, which interviews friends and experts about the late sports star.
What is Chronic Traumatic Encephalopathy (CTE)?
Hernandez's brain was donated to Boston University, which has a specialist CTE centre dedicated to researching the condition.
According to the university, CTE is "a progressive degenerative disease of the brain found in people with a history of repetitive brain trauma".
The condition occurs when repeated trauma to the brain – both due to concussions and other hits to the head – triggers brain tissue to degenerate as well as a growth in an abnormal protein known as tau.
Changes in the brain as a result of CTE can take just months or many years to develop, with some cases reported in athletes who haven't played sport since high school.
CTE has been found in boxers since the 1920s, but more recent research has discovered cases in ice hockey and NFL players.
There is no cure for CTE and it can eventually lead to dementia but not before other symptoms appear.
Aaron Hernandez is tackled during a game for the New England Patriots in 2013. Photo / Photosport
Common CTE symptoms include impulse control problems, impaired judgment, memory loss, confusion, depression, movement abnormalities such as hand tremors and – in Hernandez's case – aggression.
Did CTE cause Herandex to kill?
Lawyer Patrick Haggan, who was the prosecutor on Hernandez's second murder trial, believes his posthumous CTE diagnosis explains a lot of his behaviour.
"I started to look at the signs of CTE – impulsiveness, rash decisions, sometimes propensity to be violent. It was Aaron Hernandez," he said in the Netflix documentary.
"And if you look at everything that this young man had going on – not only physically but mentally, emotionally, from what had happened when he was a child, and what had happened in his own life, then on top of it you add the CTE – it all made sense that this tragedy had probably begun, or the seeds of this tragedy had started, many, many years earlier."
Mr Haggan also admitted he first thought the decision to donate Hernandez's brain was "just a publicity stunt of some sort" until he saw the results.
According to neuropathologist Ann McKee, an expert in neurodegenerative disease at Boston University's CTE centre, Hernandez's case was severe.
"He had a very advanced disease. And not only was it advanced microscopically, especially in the frontal lobes, which are very important for decision making, judgment, and cognition," she said in Killer Inside.
However, another former New England Patriots player believes blaming Hernandez's behaviour on CTE isn't fair.
"I think it's a cop-out," Jermaine Wiggins told Killer Inside. "There are thousands of former football players out there that might have dealt with concussions. I've dealt with them, so to use that as a cop-out? No, we're smarter than that, people."
Hernandez's secret sex life, fiancee speaks out
Also examined in Killer Inside was Hernandez's upbringing in a home marred by domestic violence as well as his secret sexual relationships with other men.
Hernandez had been sexually abused as a child by a male babysitter and lived in fear of his domineering father, who was also homophobic.
Former teammate Dan Sansoucie detailed his five-year sexual relationship with Hernandez, which he said began when they were in year 7.
Mr Sansoucie told Killer Inside that Hernandez was "terrified of his father finding out" about them.
"Mr Hernandez was a man's man who would slap the fa**ot right out of you," he said. "We had to hide what we were."
Meanwhile, since the release of the Netflix documentary over the weekend, Shayanna Jenkins-Hernandez, who was engaged to Hernandez at the time of his death, has announced she is retreating from social media.
Hernandez and Ms Jenkins-Hernandez were high school sweethearts who became engaged in 2012, with the NFL player calling her his "soulmate" in his suicide note.
She took Hernandez's last name even though the pair never married and stood by him during criminal proceedings and subsequent jailing.
For now, Ms Jenkins-Hernandez's Instagram profile remains active; however, she has not shared anything on it since her announcement.
Ms Jenkins-Hernandez is the mother of Hernandez's daughter Avielle Janelle. She is now engaged to football player Dino Guilmette, who she shares a second daughter with.
WHERE TO GET HELP:
If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call police immediately on 111.
