As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING EN ROUTE CRUISE A BEEPING NOISE WAS HEARD COMING FROM THE CARGO AREA. THE F/A WENT TO EACH PASSENGER AND ASKED THEM IF THEY HAD ANY DEVICE WITH AN ALARM ON IT IN THEIR CHECKED BAGS. NO ONE ON BOARD CLAIMED TO HAVE ANYTHING. MAINTENANCE CONFIRMED THERE WAS NOTHING MECHANICAL IN THAT AREA THAT COULD MAKE THE NOISE. THE CREW DECLARED AN EMERGENCY AND DIVERTED TO IAD AS A SECURITY PRECAUTION.