Strictly speaking, the runner did leave before the ball left the pitcher's hand (since it never left), and strictly speaking the IP is a delayed dead ball, not an immediate dead ball, so even with the IP call by the PU, the ball is still live until the play completes.
This question came from the NFHS board so I used their rules for my answer, which was
Dead Ball, IP, and send R1 to 2B.
Though the basic pitching rules are the same in ASA or FED, there are differences which require a different ruling on the field. (OK, we wont argue about which are better, but you know my feelings!
) In ASA the penalty for
all IPs is delayed dead ball, then make a ruling based on the subsequent action. NFHS differentiates between types of IPs and allows for immediate dead ball on some infractions (i.e., foreign substances or throwing to a base). If F1 spits on the ball, we dont wait for the pitch, we call IP right now, make the awards and clean the ball.
To our specific case, NFHS has an extra five words (that I have highlighted) that are different from ASA. The applicable rule is 6.1.4 "no motion to pitch is made without immediately delivering the ball to the batter. The penalty is illegal pitch; ball is dead at the end of playing action,
if the ball is pitched.
A delayed call is necessary to allow the batter to hit the IP, and then take either the play or the penalty.
If she doesn't pitch the ball there is no reason for a delayed dead ball. Call dead ball immediately, thus the ball was dead before R1 left the base.
I am sure that the hand had passed well beyond the release point before we recognized that the pitcher failed to let go. I will retroactively re-create the order, and say that the IP point, and thus dead ball, occurred the instant the hand passed the hip without releasing. And that was prior to the runner leaving the base.
WMB