As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW REPORTED THAT UPON ENTERING THE ACFT THEY OBSERVED ILLUMINATED EMERGENCY EXIT LIGHTS IN THE CABIN. UPON OPENING THE FLIGHT DECK DOOR THEY OBSERVED THE EMERGENCY LIGHT SWITCH IN THE ARMED POSITION. THEY ASKED THE F/A HOW LONG THEY HAD BEEN ON THE ACFT AND THEY SAID AT LEAST .5 HOUR AND THE LIGHTS WERE ON THE ENTIRE TIME. THE ACFT WAS REMOVED FROM SERVICE. R & R BATTERY PACKS IAW AMM 33-51-17.