Does this poker situation seem suspicious? Horseshoe Casino/Chicago

I am holding King/8 of clubs.

Flop comes out Queen (diamond) King (hearts) 8 (spades)

First player bets $70, second player folds, third player calls $70, comes around to me.... I raise to $400.

The player behind me, the button, goes all in for $428.

Two $70 callers both fold, comes around to me, obv I put in $28.

Now he's all in and there's no betting action left.

Button is holding a hand as 6 - 7 off suit (hasn't shown yet but this is what he has)

Turn comes out a 9 of diamonds, river comes 5 of spades.

Player catches runner, runner straight.

In all my years of playing poker, I have never seen a scenario like this. This player calls a $400 raise on the flop with QK8 showing holding 6/7 at a $500 max buy in table needing  

runner, runner for a straight... 

Anyone? 

Poker sucks but I would look to play with that Donkey again.

Better Luck

complete sidenote - why re-pop there to $400?  you dont see any draws you are trying to make pay for it and a hand like QK has you dominated already with one player still behind. Why not re-pop for say $200 and see what comes on the turn?  Granted, the player most definitely was going to stick around at that point being open ended, but at least you'd have more info and can make a laydown to something like a QK or possible open-ender/flush draw.  I think you still make the call but at least you have more info, rather than pot committing yourself on the flop.

not judging/critiquing, just more curious than anything else.  

ty

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