What was found
(CAN) ACFT WAS IN FLIGHT, AT CRUISE SPEED, 4TH LEG OF THE DAY RT ENGINE, WITHOUT ANY PRIOR INDICATIONS, SHUTDOWN. FOLLOWING ENGINE SHUTDOWN CUT OFF AND FEATHER WAS PULLED PROPELLER MOVED TO THE FEATHERED POSITION. NO ENGINE RESTART WAS ATTEMPTED. ON GROUND CHIP DETECTOR EXAMINED AND FOUND TO HAVE METAL PARTICLES. OIL FILTER INSPECTED ON GROUND AND ALSO HAS METAL PARTICLES. REASON FOR ENGINE SHUTDOWN STILL UNKNOWN, FURTHER INVESTIGATION TO BE CARRIED OUT PENDING REPORT FROM ENGINE O/H SHOP.