Criminal Law Questions? Ask a Criminal Lawyer.
A police officer allowing a civilian ride along to participate in a search of a vehicle would be most unusual and probably a violation of departmental policy.
On the other hand, a police officer in need can call upon the assistance of any person to help him. Nevertheless, it is hard to imagine how a vehicle search by a civilian ride along would be justified by this principle.
A search by a civilian at the direction of a police officer would be subject to the same legal requirements for admissibility of the evidence as would apply to a search by the officer himself.
Therefore, I suggest you discuss this in detail with your attorney to see whether, under all of the circumstances, the search was legal and, if not, whether you should make a motion to suppress anything that was found.