The 27-yr-old ex-NFL star had just been acquitted in a double murder case on Friday and his lawyer Jose Baez had told TMZ Sports he believed Hernandez had a real shot at getting a previous murder conviction overturned.

But Wednesday morning, officials at the maximum security Souza-Baranowski Correctional Center in Massachusetts found Aaron dead in his cell.

"Mr. Hernandez hanged himself utilizing a bed sheet that he attached to his cell window," a rep for the Massachusetts Department of Corrections said in a statement.

"Mr. Hernandez also attempted to block his door from the inside by jamming the door with various items."

Officials say Hernandez was discovered at 3:05 AM on Wednesday morning, and they tried to save his life. He was transported to a nearby hospital where he was pronounced dead at 4:07 AM.

A prison official told local news there does not appear to be a suicide note at the scene.

Aaron is survived by his 4-year-old daughter.

FYI, the Souza-Baranowski CC is considered one of the most high tech maximum security prisons in the country with hundreds of security cameras installed all over the facility.

Officials say they're investigating -- we're guessing there will be TONS of security footage to go through.

Hernandez was serving a life sentence for the 2013 murder of Odin Lloyd. He had also been on trial for killing Daniel de Abreu and Safiro Furtado near a Boston nightclub in 2012 but was found not guilty of murder in that case.