I tried asking some cops and lawyers about this law, for researching my story, but they are in disagreement over it. Basically in my story, the main character, a cop wants to use evidence against the villains, which is a recording of a conversation. But since the MC did not have a warrant to get the recording, it is normally not admissible in court. So I thought that the MC could plant the recording at a crime scene, where it will be found by other officers. I was told by a couple of cops that it can be used if it's found at a crime scene, cause at a crime scene any evidence found can be used in court. But others told me that this is not true, and in order to use a recording, the source of the recording has to be known, or it cannot be admitted. Does anyone know the truth on this when it comes to U.S. law?