The World of Real-Life Private Investigators: Naming Sources, Credibility in the Courtroom

Are Private Investigators Required to Name Their Sources?

Are Private Investigators Required to Name Their Sources?

"Never tell anybody anything unless you're going to get something better in return."
-- V.I. Warshawski in Deadlock by Sara Paretsky

Answering Writers' Questions about Private Investigations

As some of you know, I managed a private investigations agency for a decade, during which time my partner (now a trial attorney) and I also taught courses to writers at regional and national conferences on developing plausible PIs and sleuths in their stories.

As some of you are writers, and others curious about the real-world of PI, I'll occasionally post  writers' questions about the field of private investigations, and our answers.   

Today the questions concern whether or not a private detective is required to divulge his/her sources, and a PI's credibility when giving testimony.


Unless there's a state statute protecting a PI's sources, a PI can be ordered by the court to reveal her sources.

Unless there's a state statute protecting a PI's sources, a PI can be ordered by the court to reveal her sources.

Writer’s Question: You know how reporters don’t need to name their sources – what about P.I.s? Do they need to name theirs?

Answer: PIs working for attorneys cannot reveal sources to third parties without the attorney's permission.  If a P.I. isn't working for an attorney, and there is no state statute protecting the P.I. (some state statutes create a legal privilege ensuring confidentiality for P.I.s and their sources), then the P.I. can be ordered by the court to reveal her source. Under these circumstances, if a PI is on the witness stand, and she refuses to identify her source for information, she could be held in contempt of court and jailed or fined.

Writer’s Question: Who is more likely to be believed in a courtroom, a policeman or a P.I.?  Here’s my take -- the police are trustworthy, unimpeachable, and are therefore more likely to get the benefit of the doubt over a P.I., who’s …how can I say this…not as respected?

Answer:  Police usually win the credibility battle and the best way for a PI to contradict them is to have objective, physical evidence.  A P.I investigating a case, which may involve re-visiting a crime scene days or weeks later, works to gather compelling, objective evidence that can be used to counter or even refute what the P.I. has read in the police reports, and discredit police testimony.

Can a PI buoy his credibility in a courtroom?

Can a PI buoy his credibility in a courtroom?

For instance, if an officer testifies that it was plausible for a witness to "hear" three gunshots from a residence on the corner, the officer might be best contradicted with an audio tape made from the witness's home by the P.I., who probably visited the crime scene long after the police closed it down.  This audio recording would prove that it's impossible to hear any gunshots, much less three, from that distance.  After the jurors hear the tape, it is more likely the police will be completely disregarded on this issue, and possibly disbelieved on other key issues as well.

A P.I.’s contradictory evidence can also be new data the police missed.  For example, we had a case where a rancher had been charged with multiple counts of first-degree attempted murder, based on the “victims’” testimony that the rancher had shot at them, trying to kill them. The rancher insisted he’d fired in self-defense, but had no witnesses as the event took place in the middle of 800 acres of ranch land. Three weeks later, we were hired by the attorney representing the rancher, now in jail awaiting trial. It took us multiple visits to the ranch, each time meticulously checking the ground with metal detectors, before we found the bullets fired by the rancher embedded in the ground.  Their placement proved the rancher had indeed fired them as warning shots, away from the direction of the “victims,” in self-defense, and the D.A. dropped the charges.  This is an example of how P.I.s’ tangible evidence reversed law enforcement’s charges.

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