Donk bet on turn after Ace falls

[johnnymac]

Villain here was 52/10/1.6 after 73 hands. No other reads, he had not done anything that stood out to me and seemed to be pretty straightforward.

My feeling was he either had Ax and had bet on the flop as it was checked to him, or worse had A5 or A7 and had made two pair. Should I have gone to the river here?

Party Poker 2/4 Hold'em (8 handed) FTR converter on zerodivide.cx

Preflop: Hero is Button with K[img]/images/graemlins/club.gif[/img], T[img]/images/graemlins/diamond.gif[/img].
UTG calls, UTG+1 calls, <font color="#666666">2 folds</font>, CO calls, Hero calls, SB completes, BB checks.

Flop: (6 SB) T[img]/images/graemlins/heart.gif[/img], 7[img]/images/graemlins/heart.gif[/img], 5[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(6 players)</font>
SB checks, BB checks, UTG checks, UTG+1 checks, <font color="#CC3333">CO bets</font>, <font color="#CC3333">Hero raises</font>, SB folds, BB folds, UTG calls, UTG+1 folds, CO calls.

Turn: (6 BB) A[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
UTG checks, <font color="#CC3333">CO bets</font>, Hero ???