Jose Baez, the family's attorney, said arrangements were already made to donate the football player's brain to Boston University's Chronic Traumatic Encephalopathy Center, a world renowned leader in CTE research.
Baez, who successfully defended Hernandez in his most recent trial, on Thursday said the medical examiner's office had turned over Hernandez' remains to his family but retained his brain.
A top MA official says the medical examiner will release Aaron Hernandez's brain to Boston University for research as soon as the investigation into his death is completed.
Aaron Hernandez's death was ruled a suicide Thursday by MA officials, who also said that his brain would be released to an academic centre that has researched the links between brain disease and football. The state medical examiner's office also declined to comment on the status of its autopsy or the release of Hernandez's body.
Dan Bennett, Massachusetts' secretary for public safety and security, said that Hernandez's brain would be released to researchers soon. Investigators found three hand-written notes next to a Bible in the cell.
"There were no signs of a struggle, and investigators determined that Mr. Hernandez was alone at the time of the hanging", the statement read.
Cardboard had been jammed into the door tracks of his single-inmate cell to impede entry, according to the statement.
According to law enforcement sources, as reported by several Boston TV stations, Hernandez had "John 3:16" written with a red marker on his forehead.More news: Oil well in Alaska shut down after oil spill - still spewing gas
Prosecutors said he gunned the two men down after one accidentally spilled a drink on him in a nightclub.
Baez also plans to have "arguably the best forensic pathologist" Dr. Michael Baden perform an independent autopsy on the body.
Within hours of his arrest for the 2013 shooting, the Patriots sacked Hernandez, considered one of the top tight ends playing the game. Just last week he was found not guilty in the murders of two people back in 2012, and they say he was optimistic about his appeal in the Odin Lloyd murder in 2013. "If we don't get answers and answers quickly, we're going to court", she said.
"It's our position that they are holding Aaron Hernandez's brain illegally", Baez said.
The 5,800-square-foot, five-bedroom, seven-bathroom house he bought near Gillette Stadium for $1.3 million in 2012 is still up for sale.
DailyMail.com has learned a guard at the prison has been suspended on full pay for allegedly failing to make a proper inspection of Hernandez's room at 2 am.