Kentucky State Police are searching for motive as they investigate the fatal shooting of a district judge by a sheriff after the two had an argument inside the judge’s chambers, according to police.

Blue lights flashed in the background Thursday night as a Kentucky state trooper gave reporters details that state police had pieced together about a judge’s courthouse shooting death — allegedly by the county’s sheriff.

The police say a sheriff shot District Judge Kevin Mullins inside the courthouse on Thursday afternoon before turning himself in.