It is believed that there is a recording device hidden in the office.
Yes. other then in bathrooms or locker rooms where people disrobe an employee should have no expectation of privacy in the office or vehicles of an employer.
Some states have begun to require notice to employees before monitoring. I am not an Arizona attorney and cannot tell you if Arizona is one of those states. The movement began with a California statute.
Generally, though, an employer can monitor on the premises. There may be some limits on phone calls, but, other than what my colleague said, very little else.
[This communication is intended as general information and not specific legal advice, and this communication does not create an attorney-client relationship.]