Not sure if I fell for the oldest poker trick in the book, but is this player wily or a cheat?
In a live cash-game on the big blind I get 2 callers. I have

and just check. The flop is:

. The early position caller raises to £5 (blinds 0.50/£1), the second caller folds and I flat call. On the turn (

) he raises to £8 and I flat call. He now has just £25 remaining. On the river (

) he moves the rest of his chips over the line silently. I announce call instantly, upon which he says "what? I haven't bet yet" then pulls the chips back towards him. I then announce all in and he passes. He's a cheat...right?! When I told him he was he said he was just looking for my reaction before deciding what to do - is that even allowed?