Former pro-football player and convicted killer Aaron Hernandez has "the most severe case" of CTE Boston University researchers have ever seen, Attorney Jose Baez said at a news conference Thursday afternoon.

In light of the results of an inquest into the former Patriot's brain, Baez has filed a federal lawsuit against the NFL and the New England Patriots.

Baez said the results of a post-mortem study conducted on Hernandez's brain showed signs of a severe case of Chronic Traumatic Encephalopathy.

"If we knew more about it," he said. "Our client may have known more about what was happening to him."

Baez was accompanied by Shayanna Jenkins, Hernandez’s long-time fiancée and said the lawsuit is on behalf of Hernandez's daughter.

"We had a heated battle with the Suffolk county medical examiner's office for the brain of Aaron Hernandez so it could be studied by the Boston University CTE center," Baez explained. "I'd like to thank Dr. Anne McKee for all the hard work they've done. The results of Aaron Hernandez's test were positive. Aaron suffered from a severe case of CTE."

“We’re told it was the most severe case they had ever seen for someone of Aaron’s age,” he said. “[The degree in his brain] is usually found in the brain of a man 67 years of age.”

Baez encouraged people who participate in contact sports like football to consider participating in tests.

“My team has filed a federal lawsuit suing the NFL and the New England Patriots,” Baez announced. “That lawsuit was filed this afternoon."

The high-profile attorney is also set to appear on ESPN's SportsCenter Friday morning, according to his Instagram account.

Aaron Hernandez in court in Attleboro, Mass., on JUly 24, 2013.  

Credit: Boston Globe

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Credit: Boston Globe

Baez released a statement earlier this year calling for a full investigation into the football star's apparent suicide. He said there were apparently no signs that the former New England Patriots player was suicidal.

Hernandez was in the process of appealing his murder conviction, which came with a life sentence with no possibility of parole. Baez was the lead attorney on the double murder case that Hernandez was acquitted earlier this year.