Did CTE Contribute to Aaron Hernandez's Criminal Activity?

While Aaron Hernandez fought for his team on the football field, off the field he battled depression, sexual-identity issues, substance abuse and the law.

By 2017, at age 27, the star football player was dead, having died by suicide in prison after a murder conviction.

After death, he was found to have the most severe case of chronic traumatic encephalopathy, or CTE, researchers had ever seen in someone so young.

Born on November 6, 1989, in Bristol, Conn., Hernandez was a star athlete by high school. His senior year was rocked when his father—a strong and sometimes abusive force—died suddenly during routine surgery. Recruited by football powerhouse University of Florida, Hernandez left high school a semester early and showed up on the Gators’ campus at 17. The staff hoped that teammate Tim Tebow, an evangelical Christian, would help steady Hernandez.

By his junior year, the tight end was on his way to the pros. He had obvious talent, but NFL scouts knew about some iffy drug tests and run-ins with the law. He had been questioned by police in relation to a bar fight and a shooting, but was never charged.

In the 2010 NFL draft, Hernandez wasn't picked up until halfway through the fourth round when he was chosen by the New England Patriots as the 113th pick overall. The team awarded the 22-year-old a seven-year contract extension worth $41 million, with a $12.5 million signing bonus—a record for a tight end in 2012.

His new team lived by an ethos of winning called the "Patriot Way," which, according to The New York Times, "allowed Coach Bill Belichick to take chances on players with unsavory pasts." Hernandez, the youngest player on the NFL roster that season, excelled at catching star quarterback Tom Brady's passes as the team made its run to the 2012 Super Bowl. He was also known as a mercurial, difficult personality.

Brandon Lloyd, who went to the Pats that same year, was warned by another player that his locker was next to Hernandez’s locker. He was told he could expect Hernandez to behave erratically, provocatively—alternating between warm-and-fuzzy and aggressively raging.

Hernandez had a tattoo on his chest that read: "Born to play this game." But some of his other ink—a gun barrel with five bullets and a spent shell casing—would be of more interest to prosecutors in a future murder case.

In June 2013, Hernandez called his brother Jonathan to say that a friend, Odin Lloyd, had been killed and the NFL star's name was being mentioned in connection to the case. Lloyd was a landscaper and semi-professional football player who was dating the sister of Hernandez's fiancée, Shayanna Jenkins-Hernandez.

On June 26, 2013, Hernandez was arrested in connection with Lloyd's murder. Two other men were also charged.

Hours after his arrest, Hernandez was cut from the Patriots' roster.

Soon other charges surfaced—an anonymous tip linked Hernandez to a double shooting in July 2012 where Daniel de Abreu and Safiro Furtado were found shot to death in a car near a Boston nightclub.

On April 15, 2015, Hernandez was found guilty of Lloyd's first-degree murder and sentenced to life in prison without the possibility of parole.

Hernandez told others he felt oddly secure in his cell at the Souza-Baranowski Correctional Center in Shirley, Mass., reading Harry Potter books, playing cards and warming up snacks in a prison microwave.

On April 14, 2017, while serving his sentence, Hernandez was acquitted in the 2012 double murder. A few days later, on April 19, Hernandez died by suicide in his cell. The scene was gruesome, with writing on the wall in blood and the former pro football player hanging from a sheet tied to window bars.

According to The Boston Globe, another inmate told authorities that, before his death, Hernandez had been smoking K2, aka synthetic marijuana, in his cell. The drug can be difficult to detect in routine tests, and a toxicology report for it came back negative.

Hernandez left notes for loved ones (his fiancée and their young daughter) and his lawyer, Jose Baez, who also represented Casey Anthony at her murder trial.)

Jonathan Hernandez's book offers poignant details about his brother's childhood: head injuries he had endured, alleged sexual abuse he had suffered and life with their abusive father.

He also noted that the former Patriots palyer's bedding in college was from the animated movie Cars. Jonathan wrote that when his brother played for the Patriots, he slept with a knife by his bed because he feared someone was after him. Hernandez's sexuality had been the subject of rumors for years.

Fiancée Jenkins-Hernandez wanted answers, which is why she agreed to donate Hernandez's brain to the Boston University CTE Center. "If I could potentially help someone else, why not do it?" she told Baez, according to the book Unnecessary Roughness: Inside the Trial and Final Days of Aaron Hernandez. "If examining the condition of his brain can help others, especially football players, Aaron would be pleased. It's like he's back on a team again."

After Hernandez's death, his conviction was vacated since it was under appeal when he died.

There are many unknowns when it comes to CTE, first recognized in 1928 in "punch-drunk" boxers. "There's no way to diagnose CTE when someone is alive," neurologist Charles Bernick, associate medical director and primary investigator of the Professional Athletes Brain Health Study for the Cleveland Clinic Lou Ruvo Center for Brain Health, tells A&E Crime + Investigation. The brain must be examined at autopsy.

When BU scientists looked at Hernandez's brain, they found one of the most severe cases of CTE they had seen in a man of that age. Exposure—frequent, repetitive and forceful hits to the head—is the most significant known risk factor, according to Bernick.

Hernandez spent years on the playing field, but as a Patriot, he was on the injured list with a concussion only once.

Throughout his life, Hernandez showed many CTE symptoms, which can be cognitive, motor or behavioral (including depression, anxiety, explosive behavior and impulse control). But criminality is a complex impulse that encompasses more than just brain trauma. "You have factors related to childhood experiences and drug or substance abuse, and then throw head trauma in there—to just tease out the cause would be very difficult in anybody," Bernick says.

Other NFL players with severe CTE, such as former Patriot Junior Seau, have died by suicide themselves, but the link between suicide and CTE is also unproven.

The goal is to identify all risk factors and symptoms, leading to a "personalized medicine," Bernick says, that would do more than "just saying, generally, getting hit in the head is bad for you." One idea: A combination of brain imaging and a blood test could someday identify your specific risk. Then you could decide whether or not (or at what age) to play contact sport where CTE is an issue, like boxing, MMA, motocross and rodeo.

The games themselves also need to change. "As much as people criticize the NFL and NCAA (National Collegiate Athletic Association), they have at least made actual policy changes such as reducing contact in practice or the type of hits people get," Bernick says.

In September 2017, a lawyer for Jenkins-Hernandez and the couple's daughter, Avielle, announced a $20 million lawsuit against the NFL and the Patriots, who "were fully aware of the damage that could be inflicted from repetitive impact injuries and failed to disclose, treat or protect him from the dangers of such damage." The family dropped the suit the following month, but left open the possibility of refiling in a different court.

In September 2018, Ursula Lloyd, the mother of Odin Lloyd, settled a wrongful-death lawsuit with the estate of Aaron Hernandez for an undisclosed amount.