Heads up on river question

[SenecaJim]

5-10 live.

Few limpers. I complete sb with J [img]/images/graemlins/diamond.gif[/img] T [img]/images/graemlins/club.gif[/img]
Flop comes J [img]/images/graemlins/heart.gif[/img]4 [img]/images/graemlins/diamond.gif[/img]A [img]/images/graemlins/heart.gif[/img] I bet out. 3 callers.

Turn is J [img]/images/graemlins/club.gif[/img] I bet. One caller. MP player. Fairly new to table. Only seen him in 3 or 4 hands but not there long enough to get much of a read. Average on loose/tight, mostly passive.

River is the 4 [img]/images/graemlins/heart.gif[/img] I do my little studying the board with a puzzled look act and bet out. He raises. I re-raise. He 4 bets it. At first I figured flush and yippee. He raised with it. On the 4 bet, which is usually a cap but not since heads up, I start to wonder. Now I'm thinking probably gonna split the pot.

No way he would 4 bet flush with 2 pairs on board. But maybe he had AJ. Most of the passive players at table would not raise pre-flop with this in mp. And then on turn, you know, figured he was trying to be crafty mabye with J's full of Aces. But,that's the only hand that can beat me besides pocket 4's or pocket A's. Should I reraise here or just call?