What was found
(CAN) THE ACFT WAS FLYING AT 21000 FT WHEN THE PILOT HEARD A LOUD SOUND COMING FROM THE ENGINE AND THE ACFT STARTED TO VIBRATE. THE PILOT SHUT DOWN THE ENGINE AND LANDED SAFELY AT AN AIRPORT WITH NO DAMAGE TO THE ACFT. THE PILOT REPORTED PRIOR TO TAKEOFF THAT THE OIL LEVEL WAS LOW ON THE SIGHT GLASS, BUT STILL IN THE EMM LIMITS. AFTER THE EVENT, THERE ARE REPORTS THAT THERE WAS NO OIL ON THE SIGHT GLASS, ON THE DIP STICK AND AT THE OIL FILTER, BUT THE FILTER CONTAINED METAL SHAVINGS.