Violation or not?

[Workin2hard]

Considering this is only me second year as a ref, I want to get the correct ruling on a free throw issue. The free thrower shoots her last free throw and the ball hits the backboard and drops into the lane. My partner who is the trail looks dead at me in the C and waits for me to blow my whistle. Later after the game both my Partners ask me why I didn't have a violation on the shooter. I thought the ball had to hit either the rim OR THE BACKBOARD. Was I correct? Mind you these two officials had a combined 13 years under their belts.