Can an investigating magistrate later serve as judge?

That is one of the questions raised in the failed putsch trial currently going on in Burkina Faso. The president of the court has refused to recuse himself, and the Court of Cassation has refused to intervene. Details of the legal issues can be found here in a column by Amadou Traoré. Excerpt:

"This article answers three questions. The first is that the accused has the right to challenge members of the military court. The second is that it is also the duty of every magistrate in a military jurisdiction to disclose the alleged grounds for disqualification attached to his person so that the Tribunal may decide by reasoned decision. The third is that the grounds for recusation are identical to those of the ordinary courts according to the classification of the offense."