It seems that it did.
I'm not sure why, though. If the jury thought it more likely than not that the copper was lying, but wasn't sure what had really happened to make him lie, they could have returned an open verdict. They in fact decided that it was more likely than not that the copper had thought he had seen a gun as he had described, despite also deciding that it was more likely than not that Duggan had thrown the gun away before that moment.
I can't think of any adequate way to describe that. Whatever the difficulties of the procedure, it is
absurd, perverse, nonsensical.