Aaron Hernandez spent nearly four years in prison before being found hanged in his prison cell on Wednesday morning in an apparent suicide.
Authorities said Hernandez used a bed sheet to hang himself in his jail cell just days after he was found not guilty for the 2012 murder of two men.
"I don't believe that he would have killed himself", he added.
In a statement, his lawyer said there had been no warning signs that Hernandez was planning to kill himself.
The former New England Patriots tight end was already serving a sentence of life without parole for another murder in 2013.
Hernandez committed suicide on Wednesday morning according to the state corrections department in MA.
Mr. Hernandez's suicide came on the day some of his former teammates would be visiting the White House to celebrate their recent Super Bowl victory.
The cell was processed by State Police Detectives and Crime Scene Service Troopers.
Aaron Hernandez's family has chose to donate his brain to medical researchers, his lawyer, Jose Baez, said at a press conference Thursday.
Aaron Hernandez's attorney says that the state medical examiner's office is keeping the former National Football League player's family from donating his brain to research.
Fallon said he was not aware of any suicide note.
One of Hernandez's attorneys in the Lloyd case, John Thompson, says once he gets the death certificate he will file a motion to quash Hernandez's conviction.
"Basically what this means for Aaron Hernandez is that he will have in fact died an innocent man", Healy said.
Chilling details are emerging from the scene surrounding the apparent suicide of former Florida TE Aaron Hernandez. But no matter how Aaron Hernandez died, I hope in the final seconds of his short life, he found some peace. Hernandez was found hanging from a bedsheet in his prison cell at about 3 a.m. on Wednesday, according to officials.
Hernandez's agent said he doesn't believe that he would have taken his own life, as Hernandez's lawyers said they are looking to start their own investigation, which is on top of the investigation now being done by the District Attorney's office.
It was the last act in the downfall of an athlete who once seemed to have everything - including a five-year $40 million contract extension - and threw it all away. Today my heart hurts as I got the worse news I could have imagined.
He was pronounced dead about an hour later at UMass-Memorial Health Alliance Hospital in Leominster, according to a statement from the Massachusetts Department of Correction. The Patriots released him hours after his arrest in connection to the murder.