Investigative agencies are often asked whether it is legal to tape a phone conversation or not. The simple answer is: it depends. U.S. federal law does allow the recording of a phone conversation with the consent of only one party. However, individual states have their own laws regarding the recording of telephone calls.
39 states adopt what we call the “one-party consent” rule, whereby only one party needs to consent to the recording. The other party does not need to be informed so long as one of the parties has consented. Alabama, Georgia, Nebraska, New York and Texas all have this law. You cannot record your spouse’s conversation with his mistress (without one of them consenting), but you can record his conversation with you and possibly even your minor child. In general, you as a parent can provide consent for a minor.
11 states adopt the “two-party consent” rule, which require all parties to consent to the recording of phone conversations. California, Maryland, Florida and Washington all ascribe to this law.
So that begs the question: what if you wish to record a phone call between yourself (a consenting party), who lives in New York and another non-consenting party, who lives in Florida? In general, you should air on the side of caution and adhere to the stricter of the two laws. If you choose to record a conversation between yourself and a non-consenting party who lives in a two-party consent rule you run the risk of the evidence obtained not being admissible or worse, being subject to legal penalties.
Third parties cannot record your phone calls (the exception would be of course by warrant obtained by law enforcement). The Federal Communications Commission (FCC) regulates the ways telephone companies can record phone calls. Verbal or written consent must be obtained by all parties. Notification must be given prior to the start of the phone conversation that the call is being recorded.
Each state will treat evidence obtained by a recording differently. For example, in New York, you may lawfully record a conversation between yourself and your ex-spouse. However, the conversation will be considered hearsay and not admissible in court.
So the bottom line is: no, a private investigator cannot secretly record phone conversations as a part of his investigation. However, if you live in one of the 39 states that allows for one-party consent, you may be able to record a conversation so long as you can obtain consent from one of the parties. Without being able to use the information in court though, it may be of little value.
You may also be surprised to hear that a private investigation firm cannot dig through your phone records either. Such records are private and governed by federal statutes.
That is not to say that Private Investigators don’t have a number of other useful tools that produce similar results and will be admissible in court. Investigators use high-tech camera equipment and other recording devices to obtain evidence that your spouse is cheating, your employee is able to work, or your friend – the one that skipped town without paying you back that $50,000 he borrowed – is actually gainfully employed and fully capable of paying you back.