Why was there a criminal investigation?

[Manti]

Why was a criminal investigation launched involving a prosecutor? Is this standard practice, even if there is no suggestion that any foul play is involved?

This is something I never really understood about the DPI.

[eurocentric]

Probably because they realised early on that the UPI were guilty of criminal negligence in not raising the alarm sooner and also not being able to provide adequate information about the hikers route. Ultimately such prosecutions were made.