Simplify the following text for a Grade 11 native English-speaking person.
Original: The case against the three women collapsed `` spectacularly '' when the chief prosecution witness , Grace Sowerbutts , was exposed by the trial judge to be `` the perjuring tool of a Catholic priest '' .
Simplified: The case against the three women collapsed `` spectacularly '' when the main witness , Grace Sowerbutts , was shown by the trial judge to be `` the perjuring tool of a Catholic priest '' .