The incident started in the Point O Woods development, when the caller told police someone was waving a gun out the window of a vehicle on Bergerville Road, police said.
The minivan was pulled over near the Howell Township Library. Police investigating the report found the firearms were legally owned and properly secured in locked cases. They were stored in a rear cargo area of the minivan.
The minivan's occupants were on their way to a shooting range and had stopped at the library to drop off a passenger, police said.
"At this point we believe the caller either embellished or fictitiously reported this incident after seeing the occupants loading the gun cases into the vehicle," police said in a statement. "We have now turned our investigation towards the caller for possible criminal conduct."
Click here to follow Daily Voice Middletown and receive free news updates.