Aaron Hernandez may be in trouble again.

The former New England Patriots tight end, who was convicted of murder in April, was involved in a prison fight, CNN reports, while acting as a lookout during a disagreement between two inmates who, CNN says, have gang ties.

Hernandez was sentenced to life without parole and is doing his time at the Souza-Baranowski Correctional Center in Shirley, Mass. He is appealing his conviction for the June 2013 murder of Odin Lloyd.

A spokesman for the Massachusetts Department of Correction had no comment for CNN, which reported that Hernandez stood guard as an inmate entered the cell of a third inmate and began a fight Monday night. Hernandez fought with another prisoner at the Bristol County jail while he was awaiting trial.

Hernandez has also been charged with an earlier double-murder in the Boston area and could learn his trial date Thursday.