do you fold KK to this turn ace?

[A_C_Slater]

I forgot to add that even though he may have a hand like 88 or 99 that he would continue to bluff the river with he may also call the turn raise and check the river, therby you make the same anyway along with all the previous advantages I stated. I've seen this may times. I'll raise the river with my 2nd pair after a donk and they call with 3rd pair anyway hoping to hit trips on river.