The district attorney's office in Worcester County, Massachusetts has officially ruled that Aaron Hernandez's death was a suicide. 

According to ESPN, investigators said Hernandez, who was serving a life sentence for a 2013 murder, was alone in his cell at 8pm when the doors were locked and nobody had entered until a guard saw him hanging at 3am. Hernandez had jammed cardboard into the door tracks to impede correction officers from entering his cell.

Additionally, investigators found three handwritten notes next to a Bible. The notes were reportedly addressed to his fiancee and daughter, telling them he loved them and would see them in heaven.

Hernandez's family is looking to donate his brain to science for CTE research.