What was found
ENGINE OIL LEAK. FIXED LEAK, RAN ENGINE, NO OIL LEAK WAS FOUND. DURING DEPARTURE, HEARD A NOISE IN AFT SECTION OF PLANE AND NOTICED A VIBRATION. SHORTLY AFTER, A SLOW DECREASE IN OIL PRESSURE ON ENGINE NR 1. BETWEEN 60 AND 70PSI, RAN ENGINE SECURING PROCEDURE CHECK LIST AND SHUTDOWN. DECLARED AN EMERGENCY. COMPLIED WITH ALL THE SINGLE ENGINE CHECK LISTS AND RETURNED TO LAND WITHOUT ANY FURTHER ISSUES. DURING A POST FLIGHT WALK AROUND, NOTICED THAT THE PROPELLER ON ENGINE NR 1 WAS NOT MOVING AT ALL. NO OIL OR FUEL LEAKS WERE FOUND. ENGINE IS BEING REPLACED & SENT FOR INSPECTION & EVALUATION.