Hernandez was discovered hanged in his cell by corrections officers at the Souza Baranowski Correctional Center in Shirley at 3:05 a.m. Hernandez was in a single cell in a general population housing unit, officials said.
He hanged himself using a bed sheet that he attached to his cell window. He also tried to block his door from the inside by jamming the door with various items.
Lifesaving techniques were attempted on Hernandez, and he was taken to UMASS Leominster, where he was pronounced dead at 4:07 a.m., according to Christopher M. Fallon, of the Massachusetts Department of Correction. The Massachusetts State Police is investigating.
The 27-year-old Hernandez was serving a life sentence in the 2013 killing of semi-professional football player Odin Lloyd. A jury found Hernandez not guilty of first-degree murder in the killings of Daniel de Abreu and Safiro Furtado last week.
Hernandez, 27, grew up in Bristol, Connecticut, and played for the Patriots from 2010 to 2012. About six weeks after Furtado and de Abreu were killed, Hernandez signed a five-year, $40 million contract with the Patriots and went on to play another season before Lloyd was killed. He was cut from the team shortly after he was arrested in Lloyd's killing in June 2013. He was not charged in the 2012 killings until 2014.