Aaron Hernandez, the former New England Patriots star-turned-convicted murderer, was involved in a prison fight this week at Souza-Baranowski Correctional Center in Shirley, Massachusetts, a report said. The Massachusetts Department of Corrections took disciplinary action against all three men who participated in the incident.

Hernandez served as a lookout Monday while one inmate confronted another in his prison cell, a law enforcement source told CNN. It’s unclear if Hernandez directly participated in the fight, which was described as gang-related. Hernandez was placed into a “special management section” after the incident, but the Massachusetts Department of Correction reportedly denied comment on the situation.

The former Patriots tight end has been imprisoned since the summer of 2013, when authorities arrested him in connection with the murder of his former associate Odin Lloyd. Hernandez was convicted on first-degree murder and gun charges last month and sentenced to life in prison without the possibility of parole.

This isn’t the first time Hernandez has been accused of involvement in a prison fight. He purportedly physically assaulted a fellow inmate at Bristol County Jail in Massachusetts in February 2014 after the unnamed prisoner taunted him, TMZ Sports reported. Hernandez was also accused of threatening a Bristol County Jail correctional officer’s life in 2013.

Despite Hernandez’s purported misbehavior, Bristol County Sheriff Thomas Hodgson said he was mostly polite to guards during his time in the local prison system, the Associated Press reported last month. Hodgson described Hernandez as a skilled manipulator who would try to convince guards to give him extra food and said he gets upset if he thinks someone has disrespected him.

Hernandez was briefly held at Massachusetts Correction Institution-Cedar Junction in Walpole after his conviction, but he was soon transferred to Souza-Baranowski Correctional Center, a maximum-security facility. He was initially placed on suicide watch – standard procedure for those who face life sentences.