[SkyDancer]

A video shows something flying off the craft before spinning into the river. A picture shows the craft upside down with the floats intact so it had to split after it hit since it looks intact coming down.

[VTenigma]

It looks to me like half the tail boom is missing on the way down.

[Texas Fossil]

Might have been the tail rotor that fell off.

Or the tale guard around it.

[Spacetrucker]

Not intact. Large portion of the tail section is missing, likely why it went down.