As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT PERFORMED A PRECAUTIONARY LANDING SAFELY WITH A PATIENT ON BOARD. PATIENT TRANSFERRED BY GROUND. #1 ENGINE FIRE LIGHT ILLUMINATED IN FLIGHT. MECHANIC TROUBLESHOT THE FIRE DETECTOR SYSTEM ON THE ACFT AND SYSTEMS PASSED PER THE AMM CHAPTERS OF 26-10. ACFT REPOSITIONED TO BASE AND FURTHER TROUBLESHOOTING REVEALED THAT THE AFT PROBE FAILED 5 OF 8 TEST AND PRODUCED A FIRE INDICATION AT A LOWER TEMPERATURE AS PER THE AMM CHAPTER. REPLACED AFT FIRE PROBE.