In general terms, keeping away from the specifics of this case, illegal acts can come to the attention of the chain of command in any variety of ways. The police may in fact learn of it on their own and commence an investigation. The chain of command may become aware and ask for an investigation. They may become aware of an incident and ask for legal advice as to what is the appropriate way to investigate anything that might arise. And depending upon the issue and depending upon the facts, there may be a recommendation of a police investigation or there may be a recommendation of a board of inquiry or other unit investigation. Where it's transferred to the military police, they may do an investigative assessment to see whether it is something that would fall into what they would investigate.
The process that's in place in the military is not that much different with respect to what might occur in the civilian side, particularly with respect to the role of the police and the role of prosecutors.