The death of former New England Patriots tight end Aaron Hernandez has officially been ruled a suicide. 

Per the Boston Globe, the Massachusetts state medical examiner ruled Hernandez took his own life after he was discovered hanging from a bed cloth in his prison cell Wednesday.

Per Megan Kolkmann of CBS Boston, investigators said Thursday they discovered "three hand-written notes next to a Bible in Hernandez's cell."

Hernandez's cause of death was ruled as "asphyxia by hanging," per CBS Boston.

After Hernandez was discovered in his prison cell Wednesday, a Massachusetts prison spokesman told the Associated Press (h/t the Boston Globe) he was not aware of any suicide note Hernandez left at the scene.

Massachusetts Department of Correction spokesman Christopher Fallon said Hernandez was not on suicide watch, per Mark Arsenault and John R. Ellement of the Boston Globe. 

Hernandez played three NFL seasons with the Patriots from 2010 to 2012 after playing college football at the University of Florida. He was serving a life sentence for the murder of Odin Lloyd in 2013.