AFTER DEPARTURE & AT AN ALTITUDE OF 2000 FT THE PLT NOTICED THAT THE REAR ENG FUEL FLOW WAS LOW, HOWEVER, THE ENG WAS OPERATING SATISFACTORY. THE PLT, AS A PRECAUTION, DECIDED TO RETURN TO THE DEPARTURE ARPT. WHILE RETURNING THE PLT NOTED THAT THERE WAS NO OIL PRES IND FOR THE REAR ENG, HOWEVER IT CONTINUED TO RUN. WHEN THE ACFT WAS IN THE ARPT TRAFFIC PATTERN THE REAR ENG LOST TTL PWR. THE PLT FEATHERED THE ENG AND ATTEMPTED TO LAND. WHILE ON FINAL APCH THE PLT WAS TOO HIGH TO MAKE A SUCCESSFUL LANDING. HE STATED THAT HE WAS 500 FT ABOVE THE RWY WHEN HE EXECUTED A GO AROUND. HE MAINTAINED AN A/S OF 105 MPH AND ESTABLISHED A 200 FPM CLIMB. WHEN THE ACFT WAS 3/4 DISTANCE OVER THE RWY THE PLT RETRACTED FLAPS IN INCREMENTS AND HE STATED THAT THE ACFT BEGAN TO DESCEND DUE TO WIND SHEAR, TURB & DOWNDRAFTS.THE ACFT DESCENDED INTO A POND ABOUT 1/2 MI FROM END OF RWY.A PAX DROWNED. EXAMINATION OF THE REAR ENG REVEALED THE #5 CYL WAS SEPARATED IN HALF WHERE THE BARREL & HEAD ATTACHES.