PlO 50/100 straddle $200

Hero on the button holds: AK59 with $73,000 stack.
Villain on the BB has $40,000 stack.
There is one limper from middle position and Hero on the button raises to $800, SB folds, Villain on BB calls, straddler calls, limper calls.

4 way pot. The flop came AJT The pot was $3,250, everyone checked.
On the turn the board was: AJT5

Checked to Hero who bets $3,000. Only BB calls.

River was a T. BB checks , Hero bets $4,000 into $9,250 pot.
BB raises to $17,000, Hero tanks and folds saying that the river improved his hand, but his opponent's more.

Villain showed AQ73

The two opponents had history vs each other, but i want to hear opinions about the check raise with that hand. Villain is a donk? Or is this something that you high stakes players do?

The hand was taken from a blog and it was not posted with much detail.

-pot it pre
-cbet flop
-check back river (not sure about)
-as played i`d snapfold ...villain is a genius...there are 0 hds he get value from and exactly one better hand he folds out....wp,sir!

Pot Pre, Cbet flop, cbet turn...bet river. The flop check emboldens a fish c/r on the river and no, as jaop was illuding to, the river c/r is bad/fishy. If you planned to fold to a c/r you should have checked back the river.

To give more info, ill post another hand these two played before.

50/100 without straddle, 9 players at the table, Hero from UTG has KKJ3 and raises to $350.
Villain and 3 other players call.

Flop comes A62. Hero checks, Villain bets $1,500.
Everyone folds and Hero raises to $4,000. Villain calls. Turn is 9.
Hero bets $6,000, into $10,000ish pot, Villain calls. River Q
Hero bets $14,000 into $22,000ish. Villain made a quick call showing T558 and takes it down.

villain plays regulary?and where?
this idea of c/r flop and barel it all the way is so lol.......

who is villain? he played both hands poorly

These hands were played in a greek private game. Hero is a pro. I dont think that villain is a pro also, but im not sure, probably he is a recreational player. He is a huge donk at least to my eyes. But others might consider him quite good(?), judging from the title of the blog, which was something like ''Clash of the Titans'' (in english translation). ROFL!!!
You say that c/r flop and barrel turn river is bad, cause he doesnt seem the player to lay down any flush?

c/r is questionable...i`d certainly lead...but whatever....
turnbet is for sure -ev,cuz villain will not fold even the tiniest of tiny flushes...
riverbet is lolbad....pure donation,imo...

any chance that this private game will welcome an old,fat german fish....?