Giving a suspect classified information about a crime prior to a confession is called

Mitigating circumstances

A conflict of interest

Compassionate release

Confession contamination

The answer is confession contamination. The purpose of a pursuing a confession is to hear what the suspect knew about a crime without being influenced by outside information. The confession needs to be admissable or allowed in court and by giving information to the suspect beforehand from an outside source can manipulate and contaminate the confession with information the suspect was originally unaware of and thus deemed inadmissible in court because it did not originate with the suspect and invalidates the concept of a confession.