NL50: AA keeps betting and is suddenly re-raised on river

[slickss]

<font color="black">Stack Sizes</font>
BTN: $99.05
SB: $17.2
BB: $81.70
UTG: $35.55
UTG+1: $97.95
Hero (MP): $52.60
CO: $49.75

<font color="black">Preflop:</font> A[img]/images/graemlins/diamond.gif[/img] A[img]/images/graemlins/club.gif[/img] ($0.5, 7 players)
BB folds, UTG folds, UTG+1 folds, <font color="red">Hero raises to $2</font>, CO folds, BTN calls $2, SB folds

<font color="black">Flop:</font> 4[img]/images/graemlins/heart.gif[/img] J[img]/images/graemlins/spade.gif[/img] 5[img]/images/graemlins/club.gif[/img] ($4.5, 2 players)
<font color="red">Hero bets $4</font>, BTN calls $4

<font color="black">Turn:</font> 4[img]/images/graemlins/heart.gif[/img] J[img]/images/graemlins/spade.gif[/img] 5[img]/images/graemlins/club.gif[/img] [7[img]/images/graemlins/spade.gif[/img]] ($12.5, 2 players)
<font color="red">Hero bets $8</font>, BTN calls $8

<font color="black">River:</font> 4[img]/images/graemlins/heart.gif[/img] J[img]/images/graemlins/spade.gif[/img] 5[img]/images/graemlins/club.gif[/img] 7[img]/images/graemlins/spade.gif[/img] [8[img]/images/graemlins/spade.gif[/img]] ($28.5, 2 players)
<font color="red">Hero bets $10</font>, <font color="red">BTN raises to $20</font>, Hero ?

I raise 4xBB like I always do when I raise and he calls on the button. He keeps calling my bets and I have the feeling that he is calling me down with something like KJ/QJ.

The river is a little bit ugly, but as the flush is runner-runner and the straight is a little off I value-bet to get something out of him. But his raise puts me off, he couldn't possibly be doing this for value with anything I beat. Can I call this?