throw in spot?

[bbman]

Saw this play today. Not sure if refs got it right or not.
White makes a basket. Blue gets a run the base line throw in. Blue makes a long pass down the side line. Receiver steps on side line, then (while still OOB), grabs the pass that was still in bounds. Where is white's throw in location? White coach wanted the throw in back to base line, blue coach insisted throw in be where his player stepped OOB's.
Refs brought it back to base line. We're they correct?
Please site rule reference if possible.