The death of former New England Patriots tight end Aaron Hernandez was officially ruled a suicide on Thursday, clearing the way for his brain to be tested in concussion research.
The Worcester County District Attorney's Office in Massachusetts said after an investigation into the former NFL star's death that Hernandez took his own life.
Guards discovered the body of Hernandez, who was 27, in his single cell at the Souza-Baranowski Correctional Center in Shirley, Massachusetts, early Wednesday morning and he was pronounced dead at a nearby hospital.
Chief medical examiner Dr. Henry N. Nields made the conclusion that "manner of death was suicide and the cause asphyxia by hanging," according to a news release.
Three handwritten notes were found in the cell but the contents weren't immediately released and authorities said there was no indication of foul play.
"There were no signs of a struggle and investigators determined that Mr. Hernandez was alone at the time of the hanging," the district attorney's office said in the statement.
The determination of a cause of death cleared the way for Hernandez's brain to be released to Boston University as the family had wished to undergo testing as part of the university's concussion research.
With concern over the impact that repeated blows to the head can cause NFL players and brain examination only possible after death, the Hernandez family wanted his brain to be studied.
Hernandez family lawyer Jose Baez said earlier Thursday the medical examiner was "illegally" holding the brain after releasing the body to a funeral home.
"It's our position that they are holding Aaron Hernandez's brain illegally," Baez said. "There's a fixing procedure to prepare these specimens. It is their position that they are going to be the ones to do the fixing procedure. The family does not have confidence in the medical examiner's office."
Baez said the family decided on giving the brain to Boston University to seek signs of chronic traumatic encephalopathy (CTE) -- the debilitating brain disease that researchers say is caused in part by concussions while playing American football and other head trauma.
"The family of Aaron Hernandez has decided to donate Aaron's brain to the study so we can possibly help other young men who play football ... further the cause, and possibly shed light and provide more evidence on this case," Baez said.
- Life sentence for murder -
Hernandez was serving a life sentence handed down in 2015 for the murder of Odin Lloyd.
His suicide came only five days after he was acquitted on double-murder charges in a separate case, and the timing of his death and absence of a suicide note has left many perplexed.
"There were no conversations or correspondence from Aaron to his family or legal team that would have indicated anything like this was possible," Baez said. "Aaron was looking forward to an opportunity for a second chance to prove his innocence. Those who love and care about him are heartbroken and determined to find the truth surrounding his untimely death."
Guards discovered the body of Hernandez hanging by a bedsheet from a cell window at a maximum security state prison not far from the Patriots' home stadium in Foxborough, Massachusetts.
Hernandez signed a seven-year, $40 million contract with the Patriots prior to the 2012 season. His death came on the same day the Patriots visited the White House to mark their Super Bowl 51 comeback victory over Atlanta.