On looking at the crank area I see the bottom bracket has unscrewed itself several turns... I guess this caused the locking.
Or perhaps, because its an Italian threaded Veloce bracket with a right-hand thread, it came loose because he didn't put some kind of loctite on the threads?
This is a perenial problem with Italian threaded bottom brackets and it's not difficult to sort out.
Incidentally my mate rode a mountainous sportive in Italy and had to stop frequently in the last 50 miles to hand tighten his Italian threaded b/b - unfortunately I was too tired to be smug (he always scolds me for my mechanical hamfistedness but then he does usually have a point)