Private investigators can document audio conversations that they are a party to, without having disclosing that they are recording to another events, in North Carolina. With that said, the legalities of audio recording of conversations vary from state to state. While you can study these in a very schooling application, https://pb.lib.berkeley.edu/xtf/servlet/org.cdlib.xtf.dynaXML.DynaXML?gobk=https%3A%2F%2Fntetektib-24h.gr&source=%2FBITAGAP%2FDisplay%2F1148BITAGAP.Work.xml&style=Work.xsl