Dead ball drama: Was KP really out?

Kevin Pietersen backed away just prior to Mohammad Asif's delivery, distracted by movement from behind.

But instead of allowing the ball to pass, Pietersen made a half-hearted shot which ended up as a catch to Salman Butt .

The Pakistani captain's celebrations were immediately cut short when umpire Marais Erasmus signalled a dead ball. Was KP really out under the rules?

2nd Test, Edgbaston. Aug 2010.