Maybe the officer(s) who initiated the investigation were concerned that if a supervisor or prosecutor became aware that they had knowledge of a criminal act being committed by another officer they could be subjected to civil, criminal, and/or disciplinary action.

Decisions are easier when you don't care about people, but friends and family are usually the first to put you in a trick bag.

I hope this case becomes a test case to oppose the law. Criminalizing possession of hammers, knives, and guns makes as much sense as criminalizing emotions like hate.

Be safe.