http://iscoresports.com/

There doesn't appear to be a way to account for passes knocked down at the line of scrimmages they are in fact attempts, but not passes defended (by defensive secondary) nor can you identify an intended receiver.

If you tap the QB, and select "Pass Incomplete", it lets you select the Intended Receiver, and you can also tap the ? to the right of the intended receiver and select a "Broken Up By" player.