If the private detective/investigator has probative and admissible evidence to offer in support your claims, then his/her testimony, like any other fact witness, may be considered by the trier of fact.
PI's uncover facts, find out what witnesses saw or heard and collect other information relative to a scene or an event like diagrams, photo's, statements, etc. and they can be very useful, if not critical to the outcome of a criminal or civil case. If what the PI will testify to is based on what he/she heard from another person (hearsay) or is based upon an opinion he/she formulated, the rules of evidence may limit the scope of the PI's testimony.
Consult with an attorney before engaging the services of a private detective to see whether the evidence you expect to use is going to be admissible at trial.
The information contained herein is meant for informational purposes only. It is not meant to be relied on as legal advice for any particular circumstance or situation. If you need legal advice and counsel on any matter, consult an attorney.
Any witness with relevant admissible evidence will be considered. I agree that you should be working with an attorney rather than trying to do your own investigation.
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