Did they check to see if the pennant snapped?
If it was stolen there’s a possibility it could be in St Maarten or San Juan provisioning, I suggest you report it to the US Coast Guard they Patrol the waters of the Caribbean.
Good luck.
BTW there is another serial number that’s hidden somewhere in the hull, Beneteau can let the authorities know where it’s located in case they find a similar boat with the SN removed.