5:09 PM ET
- ESPN.com news services
Aaron Hernandez's death in prison has been officially ruled a suicide.
That determination comes from the district attorney's office in Worcester County, Massachusetts.
Authorities say Hernandez's brain is being turned over to university researchers now that they've ruled his death in prison a suicide.
The DA says the state's chief medical examiner had withheld some tissue samples from the ex-NFL star's brain as part of the effort to confirm he took his own life.
Now that that's not in question, officials say the brain will be released to Boston University's Chronic Traumatic Encephalopathy Center in accordance with the wishes of Hernandez's family. The center is a leader in research into the effects of concussions on the brain — something the NFL has been preoccupied with in recent years.
Authorities say investigators found three handwritten notes next to a Bible inside the maximum-security prison cell where Hernandez was found hanging early Wednesday.
They said Thursday there was no sign of a struggle and that the former New England Patriots tight end was alone. Investigators say Hernandez, who was serving a life sentence for a 2013 murder, blocked access to his cell from the inside by jamming cardboard into the door tracks.
They say he was locked in his cell at about 8 p.m. and that no one entered until a guard saw him just after 3 a.m. and forced his way in to try to save Hernandez.
Earlier Thursday, Hernandez's top lawyer said he has retained prominent medical examiner Dr. Michael Baden to conduct an independent autopsy. Jose Baez says Baden is on tap to examine the remains of the ex-NFL star.
Information from The Associated Press was used in this report.