Explain any NTSB notifications and reporting that would be required and why?

One night, a sheriff’s department helicopter lands a SWAT team in the yard of a rural residence suspected of containing a methamphetamine lab. After the raiding party disembarked, and as the pilot was turning the aircraft in a hover to depart, the helicopter’s tail rotor contacted a barbed-wire fence and was damaged to the extent it will have to be replaced. No one was injured. Explain any NTSB notifications and reporting that would be required and why?