Which witness is correct?

 Fred Romel - "It was a horrible accident.  The blue car was turning right at the intersection and suddenly the green car drove quickly through the intersection.  He didn't even stop at the stop sign."

 Tracy Evans - "The blue car was driving through the intersection when the green car suddenly turned left in front of the the blue car, cutting him off.  That's when they crashed."

 Paul Thomas - "The blue car didn't stop at the stop sign.  He drove right into the intersection and crashed into the green car which was driving straight through."

 Ellen Fitzgerald - "I saw everything.  The green car was driving behind the blue car.  The blue car suddenly stopped at the stop sign and the green car hit him."