As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EQUIPMENT DOOR OVERHEAD LIGHT CAME ON DURING TAKEOFF WHEN GEAR WAS RAISED. AN EMERGENCY WAS DECLARED AND LANDED WITHOUT FURTHER INCIDENT. THE AIRCRAFT WAS GROUNDED. PERFORMED DOOR INSPECTION, FOUND DOOR UNLATCHED. CLOSED AND SECURED DOOR IAW 52-71-00.