SDCL § 33-10-83: Counsel may not have been investigator, military judge, witness, court member, or opposing counsel.

No person who has acted as investigating officer, military judge, witness or court member in any case may act later as trial counsel, assistant trial counsel, or, unless expressly requested by the accused, as defense counsel or assistant or associate defense counsel in the same case. No person who has acted for the prosecution may act later in the same case for the defense nor may any person who has acted for the defense act later in the same case for the prosecution.