Lumumba Sayers Sr. had murder on his mind when he went to a child’s pool party and shot a man in the head at close range in Commerce City, Colorado.

The 46-year-old MMA fighter was charged with first-degree murder and felony menacing charges for the killing of 28-year-old Malcolm Watson who Sayers Sr. believed had a hand in the killing of his 23-year-old son Lumumba Sayers Jr., according to reports.

“Witnesses had stated the [shooter’s son] had been murdered about a year ago by a friend of the deceased […] and this murder was probably in retaliation or revenge,” the arrest affidavit states.

However, a 24-year-old man named Tyrell Braxton was charged with Sayers Jr.’s murder but the charges were later dismissed. No word on what the relationship between the victim and Braxton was.

After retiring from mixed martial arts, Sayers Sr., became an active member in his community. He frequently talked about gun violence and supported change through his foundation and movement called Gloves Up Guns Down. This information was reported by LarryBrownSports.com.

Now, he’s being held on a $1 million bond at Adams County Detention Facility. He has a court appearance Aug. 15.