As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING CLIMB THROUGH 4000 FT, A LOUD BANG WAS HEARD FOLLOWED BY A VIBRATION. CREW OBSERVED NR 1 ENGINE SPOOLING DOWN. #1 ENGINE WAS SHUT DOWN AND AIRCRAFT RETURNED TO AIRPORT. NR 1 ENGINE WAS EXAMINED BY MANTENANCE AND FOUND TO HAVE SUFFERED MASSIVE FAILURE. ENGINE SENT FOR TEAR DOWN.