TOKYO - Japan's coast guard is investigating why it took nearly an hour for a deadly collision between a U.S. Navy destroyer and a container ship to be reported.
 
A coast guard official said Monday they are trying to find out what the crew of the Philippine-flagged ACX Crystal was doing before reporting the collision to authorities 50 minutes later.
 
The coast guard initially said the collision occurred at 2:20 a.m., as the Philippine ship had reported it at 2:25 a.m. and said it just happened. After interviewing Filipino crewmembers, the coast guard has changed the collision time to 1:30 a.m.
 
The ACX Crystal collided with the USS Fitzgerald off Japan's coast early Saturday morning, killing seven of the destroyer's crew of nearly 300.