As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EN ROUTE FROM CMH TO CVG RECEIVED PAX DOOR WARNING MSG. EMERGENCY DECLARED, A/C RETURNED BACK TO CMH LANDED SAFELY. INSPECTED A/C FOUND ICE OBSTRUCTING DOOR HANDLE ASSY. REMOVED ICE FROM DOOR HANDLE ASSY. OPS CHECK GOOD, NO FURTHER DEFECTS.