Investigators are trying to determine why a Kentucky sheriff allegedly shot and killed a district judge after they argued inside the judge’s chambers, according to Kentucky State Police. District Judge Kevin Mullins,

A judge was fatally shot in his chambers by a local sheriff after an argument at a courthouse in Whitesburg, Ky., on Thursday, state police say. District Judge Kevin Mullins, 54, was pronounced dead at the scene.

Kentucky State Police say 43-year-old Sheriff Mickey Stines shot and killed 54-year-old District Judge Kevin Mullins inside the courthouse Thursday afternoon. Circuit Court Clerk Mike Watts said he’s still struggling to understand what happened, as he saw both men eat lunch together just a few hours earlier.