Establishing Credibility

When we trained the LE Officers for the scene response protocols and explained why our 2 person volunteer team would be there and how we can help LE and the surviving family members a question came up from an officer. I has do to with chain of evidence since by us being at the scene, our volunteers become part of the scene. The question was if we had licensed social workers or therapists as volunteers who are bound by law to not repeat anything they hear, and if someone at the LOSS or DOSS scene implicates themselves in anyway, if LE interview our volunteers because they were on the scene, our volunteers who are licensed social workers or therapists are unable to share the information they heard which could hinder the LE investigation if it is determined a crime was committed. I think this is the scope of their question. Does anyone have experience with this situation or have an answer for how to handle it if the situation does happen? Thanks for your help with this!