According to TMZ, Aaron Hernandez is under investigation for allegedly threatening to shoot and kill a jail guard at the Bristol County Jail back in 2013, although one of Hernandez's former inmates claims that the allegations are completely untrue.  

The inmate spoke with investigators recently about claims from one Bristol County Jail guard that Hernandez once threatened to "kill the guard and shoot his family" during a heated argument.  The guard also claimed that Hernandez made a "machine gun sound" to simulate the act of shooting him down. However, the "ex-inmate was adamant Hernandez NEVER threatened the guard ... though he did claim Aaron called the guy a 'b*tch' during the heated exchange," according to reports from TMZ.  

The particular guard in question who made the claims is the same one who busted Hernandez for pulling swindles in order to get more food.  The ex-inmate who spoke to investigators explained how the guard caught Hernandez utilizing various jail tricks to get extra grub, such as eat half of his meal and then put an insect on the rest and complain to the guards in order to get a fresh serving to consume.

This particular incident earned Hernandez a behavioral write up. No calls have been answered or returned from Bristol County Jail officials regarding the investigation.

Source: tmz.com