Aaron Hernandez is in prison for one murder and is awaiting trial on double-murder charges. (Brian Snyder/Associated Press)

While behind bars, Aaron Hernandez has been involved in multiple fights, and now it appears that he was preparing for even greater mayhem. The former Patriots tight end was reportedly moved to a segregation unit after a prison-made knife, often referred to as a shiv or a shank, was found in his cell Thursday.

Hernandez is serving a life sentence at a maximum-security prison in Massachusetts after being convicted of the 2013 murder of Odin Lloyd, a semi-pro football player who was said to have been dating the sister of Hernandez’s girlfriend. The ex-Patriot is also awaiting trial for a double murder that occurred in 2012.

According to Boston TV station WHDH, prison officers found the knife while doing a shakedown of Hernandez’s cell block. He was reportedly moved out of general population and into the segregation unit, which houses inmates thought to be a danger to others or in danger themselves.

Hernandez was involved in a violent incident at that facility in May, when he was alleged to served as a lookout during a fight between inmates with gang ties. According to CNN, he was also in a 2013 brawl at the jailhouse where he awaited trial in the Lloyd case.

The 26-year-old Hernandez played three seasons with the Patriots, who drafted him in 2010, the same year the team took Rob Gronkowski. New England released Hernandez, who had been an all-American at Florida, within two hours of his arrest on the Lloyd murder charges.