Axle from duck boat in deadly crash 'sheared off'

The left front axle of the duck boat involved in a deadly Seattle accident was sheared off, but federal investigators said on Saturday they don't know if it was damaged before the collision with a charter bus that killed four international college students.

National Transportation Safety Board Member Earl Weener said the axle will be sent to a federal lab for further examination. It's too soon to know how the axle was damaged, Weener said.

Witnesses have said they saw the duck boat's left tire lock up on Thursday as it swerved into a charter bus carrying international students over a bridge. Four North Seattle College students from Austria, China, Indonesia and Japan were killed.