As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFT LAV SMOKE WARNING MSG CAME ON AFTER T/O FROM CVG WITH SMOKE IN CABIN AND COCKPIT. EMERGENCY DECLARED, A/C RETURNED TO CVG LANDED SAFELY. RAN A/C ENGINES ISOLATED PACKS, OPENED ALL CABIN GASPERS SMELL DISSIPATED TO CLEAN AIR AND NO DEFECTS NOTED. SUSPECT REMANENCE OF PRIOR COMP WASH.