I need help on call I made tonight.

[TGR]

I need help on a call that I made tonight that I believe I may have gotten wrong.
Here is the situation: A1 attempts to dunk the basketball. As A1 gets above the rim, the ball slips from his hands and goes upward about two feet. A1 then grabs the ring and pulls down on it (ball is in cylinder at this time, probably about a foot above the ring). I call basket interference and then the ball falls straight down through the net. I wave off the basket and the coach of Team A questions why it's basket interference. I state that since the ball was in the cylinder and A1 grabbed the ring that it is basket interference. At halftime, my partners and I talk about it and try to search the NCAA rulebook for the correct call. We couldn't find the information we needed.

So...Can someone please help me to know if I was right or wrong on this play. Please cite NCAA rulebook with answer. Thanks for the help. If anyone needs more information about the play, please let me know.