As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GUA - CREW REPORTED LEFT ENGINE OIL FILTER BYPASS LIGHT ILLUMINATED. ENGINE RETARDED THROTTLE AND LIGHT DID NOT EXTINGUISH. CREW SHUTDOWN ENGINE (SINGLE ENGINE TIME 5 MINUTES). EMERGENCY DECLARED FLIGHT RETURNED GUA LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED LEFT ENGINE OIL FILTER BYPASS TRANSMITTER AND OIL FILTER ELEMENT. SYSTEM GROUND CHECK NORMAL OPERATION.