£100 NLHE freezeout, c400 runners (200 each day)
50-60 runners remaining
Blinds 800/1600/100 - 45min clock
My stack 42k
Villian stack 60k
I'm in BB, Villian on Button
Villian has recently joined table but is known to me (and me to him). I remind him of the last time he bust me with a sick runner runner after a really bad play. He is still embarrassed about it and we get some bather going - in good spirit. I have good reads on him and feel by talking to him I can get good info.
Folded round to villian on button, he says "I just call" and timidly pushes the 1600 chips
SB folds and I look down at

I say "ok, you just call well I'll just check then" - he doesn't look confident
flop

I bet 4000 he calls
turn

it's me to act and he pushes all-in, dealer asks me if I checked, I say no. Villian pull his chips back and says sorry. ruling explained to him and chips go back over line and it's back to me.
I start talking again and I feel my reads are good and he is not at all confident.
What could he have?
Whats my move?