Earlier we advocated the abolition of compulsory testimonies by witnesses, because (eye) witness statements are too often unreliable. A particular type of testimony is hearsay (testimonium de auditu), which we will explain with an example:
Alice tells Bob that she has killed Carol and that she has secretly buried the body. Bob, a law-obeying citizen, informs the police, which in turn arrest Alice for murder. Since Bob has not been involved in killing Carol, his testimony is based solely upon whatever Alice has told him. This is called hearsay.
There is a fundamental problem with hearsay as evidence in criminal prosecution. We cannot know sure whether Alice was actually telling the truth, as she could have simply lied to Bob. Also Bob might have made up Alice’s confession.
For this reason hearsay is controversial as evidence and several jurisdictions do not allow such evidence at all. Similarly we oppose hearsay and its exclusion from criminal proceedings. Even if this might result in wrongful acquittals.
A consequence of this is that judges do not have to worry about something like “the seal of the confession”, i.e. the (supposed) confidentiality of things said to religious ministers during confession. If a priest or someone with a similar position learns through a confession that someone has been involved in some crime, it constitutes hearsay and as such is no reliable evidence.
Though this line of reasoning might be controversial, there is no reason to deal differently with clergy than other members of the public. Unless a minister of faith is personally involved in the crime, there is no way for him or her to find out whether anything said during confession is true, nor is this his or her duty.
Even though hearsay might not be allowed as evidence in court, it is acceptable as a cause to start a police inquiry. The purpose of such investigation is to gather (further) evidence against (suspected) criminals. The police might learn this way that some crime might have been committed or to identify persons of interests.