Page "National Transportation Safety Board" Paragraph 5

The NTSB is normally the lead organization in the investigation of a transportation accident within its sphere.

However, this power can be surrendered to other organizations if the Attorney General declares the case to be linked to an intentional criminal act, although the NTSB would still provide technical support in such investigations.

This occurred during the investigation of the September 11, 2001, attacks when the Department of Justice took over the investigation.