Ball in play, but team's 6th man still on court.

[GregAlan]

Worked a middle school girls' game yesterday. Late in the game, the coach from one of the teams calls for a sub for one of her players who had just recently collected her 4th foul. Her team also will have possession from backcourt. The new player has come in, my partner has administered the ball, and that team is bringing the ball up backcourt to frontcourt. What I notice then is that the player that was coming out on the sub [the player with that 4th foul and she was still upset on the call] was taking her time leaving the court and was still walking slowly [with attitude] off the court near her bench. The coach wasn't saying anything to her either to hurry her off the court. The ball was in play and in essence there were six players on the court for that team. I wasn't sure what the exact violation was, in fact, I wasn't sure there was a violation, but I blew my whistle, stopped the game, and gave the ball over to the other team due to the other team having 6 players on the court. My partner and I should have been more attentive in making sure the player leaving the court was actually out of the game, but we just didn't catch it.

What should have been the correct thing to do, and what, if any, violation might have occurred?

G