At the season finale of Better Call Saul: Season 2. Chuck records Jimmy admitting to committing a felony. The recording was obtained without Jimmy's permission (the tape recorder was hidden). Wouldn't this recording be inadmissible in court as it violates the wire tap law?
Better Call Saul is set in New Mexico where as long as one-person involved in the conversation is aware that it is being recorded, it is legal. Known as "one-party consent". This varies state to state.
If neither Jimmy nor Chuck knew the conversation was being recorded, then it would be illegal.
It turns out that TV is not entirely faithful to reality, so plot development may explain something. I don't know where the calls were made from and to, but if both parties are in New Mexico, the recording is legal, since New Mexico is a 1-party consent state. If either party is in California, Connecticut, Florida, Illinois, Maryland, Massachusetts, Montana, New Hampshire, Pennsylvania or Washington, then there could be a two-party consent issue. So I would check the assumption that the recording violates a wiretap law.