Alfan Apolinary @kyalubota and 3 Others vs Republic, Criminal appeal no 164 of 2021.

This case among other things explains the effect of improper conducting of committal procedings. The court hard this to say:

In the case at hand, it is apparent in the record of the appeal that
there was total non-compliance with the provisions of section 246 (2) of the CPA. It is clear that not only the statements and the substance of the intended witnesses were not read over but also the contents of the exhibits
were not revealed to the appellants.

We are aware that ordinarily the Court has been excluding the
witness’s evidence and exhibit from consideration for failure to comply with the requirement of the law on this aspect. For instance, in Samwel Henry
Juma v. The Republic, Criminal Appeal No. 211 of 2017 [2016] TZCA 813 (5th May 2016, TANZLII), the evidence of the witness together with the extra judicial statement were expunged from the record.

However, in the present case, we are of the view that since the
irregularity was to a large extent caused by the committing court and that both sides were prejudiced, it is in the interest of justice that we nullify the
respective proceedings of the committal court and those of the trial court followed by an order of a retrial before the High Court.
In the event, we allow the first ground of appeal.

Indeed, as this ground suffices to dispose of the appeal, we do not deem it appropriate to determine the second ground of appeal.