As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER TAKEOFF AND GEAR RETRACTED, THE NR 1 ENGINE PROPELLER SPEED, NP WENT TO APPROXIMATELY 400 RPM AND THE TORQUE INCREASED MORE THAN 125 PERCENT. THE CREW SHUTDOWN ENGINE AND RETURNED TO THE DEPARTURE POINT WHERE AN UNEVENTFUL SINGLE ENGINE LANDING WAS MADE. TROUBLESHOOTING IS ON-GOING .