Aaron Hernandez wrote a popular Bible verse - John 3:16 - on his forehead using a red marker pen before committing suicide in his Massachusetts jail cell, according to reports.

CBS Boston reports that the convicted killer and former New England Patriots star wrote the verse "John 3:16" in "blood red marker" on his forehead. The verse reads: "For God so loved the world that he gave his one and only son, that whoever believes in him shall not perish but have eternal life."

Hernandez, 27, also left a Bible in his cell on to that verse, according to WBZ Boston. Currently, investigators are said to be looking at the possibility Hernandez smoked synthetic marijuana before taking his own life.

The former tight-end was found hanged with his own bed sheets at 3am this morning in his cell, according to Christopher Fallon, the Assistant Deputy Commissioner of Communications of the Massachusetts Department of Correction.

"Mr. Hernandez was in a single cell in a general population housing unit. Mr. Hernandez hanged himself utilizing a bed sheet that he attached to his cell window," reads the report.

"Mr. Hernandez also attempted to block his door from the inside by jamming the door with various items. The Massachusetts State Police are on scene and the investigation continues. Mr. Hernandez's next of kin have been notified."

The former NFL star's death comes less than a week after he was acquitted of the 2012 murders of two Boston men. At the time of his death, Hernandez  was already serving a life sentence for the 2013 murder of Odin Lloyd, a semi-professional football player, according to the New York Times.

Martin Healy, chief legal counsel for the Massachusetts Bar Association, said Hernandez's death means his murder conviction will be erased under a centuries-old legal doctrine enshrined in Massachusetts' criminal case law.

"Aaron Hernandez goes to his death an innocent man under the eyes of the law," said Healy. "It's as if the case never existed."

Hernandez's lead attorney in his most recent trial, Jose Baez, said the "family and legal team is shocked and surprised at the news of Aaron's death" and vowed to conduct his own investigation regarding the situation.

"There were no conversations or correspondence from Aaron to his family or legal team that would have indicated anything like this was possible," Baez said in a statement.

"Aaron was looking forward to an opportunity for a second chance to prove his innocence. Those who love and care about him are heartbroken and determined to find the truth surrounding his untimely death."

At the time of his death, Hernandez had a daughter with Ms. Jenkins, Avielle, now 4.