As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
JUST NORTH OF PXR CLIMBING THROUGH FL310, GOT A "CABIN DOOR UNLOCKED" CAUTION LIGHT. RAN THE CHECKLIST, COMMUNICATED WITH ATC AND ASKED FOR LOWER (12000 FT). BRIEFED THE PAX, AND PROCEEDED ON TO VNY. ON ENGINE SHUTDOWN, VISUALLY INSPECTED THE CABIN DOOR AND DETERMINED THAT IT WAS LOCKED AND LATCHED FIRMLY