May I just say, at the risk of sounding like a bit of a wet blanket, that there seems to be an increasing amount of guesswork being posted.....
Speculation and guesswork are somewhat counterproductive. Logic and deduction based on facts or at least information that has been verified would seem to be more helpful.
Now I know I've posted my own theories as to what may have happened, but they were based pretty much on what we know and what was on the CCTV. Plus a little bit on his past MO (alleged).
But all this talk of guns, knives, etc I think is getting into the realms of the fanciful. As others have posted, I really don't think the police would have released the CCTV footage if it showed Jill being held at gunpoint, and I am sure she would not have walked in his direction if he was threatening her with a knife. That would NOT be a natural thing to do. As I said - to threaten somebody with a knife, you have to be right with them within striking distance.
I've also had another look at the picture from the Facebook page (yup, it seems many of us grabbed a copy while we could) and while I'm not sure just what that little brown object actually is, I'd put my house on the fact that it is NOT a knife...
OK - I'll shut up and go to bed. Early start in the morning :seeya: