Interesting river spot vs stinger

[recallme]

Ok , in my sample he´s an absolute nit. I missed a note i made few days ago, where he made a PSB with the nut flush on a 5 to a flush board. So do with it what you want, i didn`t have this information at this point, because i was too stupid to use it.

Poker Stars
No Limit Holdem Ring game
Blinds: $10/$20
6 players
Converter

Stack sizes:
UTG: $1886
UTG+1: $841
CO: $3722.35
Hero: $2157
SB: $1047
BB: $3551

Pre-flop: (6 players) Hero is Button with Q[img]/images/graemlins/heart.gif[/img] K[img]/images/graemlins/heart.gif[/img]
<font color="#cc0000">UTG raises to $40</font>, 2 folds, Hero calls, SB calls, BB calls.

Flop: 4[img]/images/graemlins/diamond.gif[/img] 4[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/diamond.gif[/img] ($160, 4 players)
SB checks, <font color="#cc0000">BB bets $140</font>, UTG folds, <font color="#cc0000">Hero raises to $380</font>, SB folds, BB calls.

Turn: 3[img]/images/graemlins/club.gif[/img] ($920, 2 players)
BB checks, Hero checks.

River: 7[img]/images/graemlins/heart.gif[/img] ($920, 2 players)
<font color="#cc0000">BB bets $840</font>

I am not sure what his line stands for. I think a draw he would either 3bet or fold on the flop. I am not sure how he would play the 4`s in his range.

Perhaps he wanted to c/r them on the turn, but i think he knows that there is the FD in my range.

Is he potting a K or total air here?


Edit: I forgot to mention that Preflop raiser was the table donk and i wanted to play with him postflop and this was the reason not to 3bet