What do we have here?

[ca_rumperee]

I'm Trail, player in front of me launches a 3, THEN I HEAR "Tweeet!". Ball goes in.

Partner has "no basket!! 3 second violation!!"

The whole thing caught me by surprise. He was waving off the shot, even before it went, but his whistle came after the shot was released.

Should I have caucused and advised what I saw (I didn't)??
The fact that he was waving off the shot made me yield.

What would we have if he is unaware of the shot?
.... count basket. Inadvertant whistle. go to a/p arrow?