Who shoots the FT's?

[Danvrapp]

Player A1 gets whistled for a push on B1. B1 reacts rather unfavorably, and grabs A1 and tosses him to the ground. Intentional foul. Turns out that the original foul on A1 was his 5th. Who shoots the foul shots for the intentional foul, A1 or his replacement. We let A1 shoot 'em, and I think we got it wrong