Consider the Exclusionary Rule in the large and small picture.

There is a homicide of a child and the perpetrator is arrested and charged.

The main evidence [does not matter what it is but consider it vital like the murder weapon] against the perp was illegally obtained. The Court rules to suppress this vital evidence. Without this evidence the prosecution's case falls apart and they cannot prosecute. Ergo: The Child murderer goes free.

Are we served as a society by the Exclusionary Rule?

How do we reconcile this seemingly unjust result? etc.

https://www.youtube.com/watch?v=YOpynkodKxE