Although possible with bsl, I highly doubt he has others in that forest unless you they were taken from about a 30-60 minute radius from that graveyard. He seems to have about equal times of dumping distance and abduction distance.
Now if he gets convicted with more which I feel highly so, they should look into small cemeteries that are 60 minutes or less from the abduction site. Abducting someone any further and driving that far with bodies is just too risky, 60 minutes is already pushing it.
I think he's strange enough to possibly dig up graves already there and just dump another body there in that grave, to make sure it's never checked. A grave that isn't often visited so that it wouldn't look like it had been disturbed.
If they begin looking for more victims, there's a small cemetery in the HOOK MAN bridge forest that I had taken pictures of a while back, the day before Mickey's body was sadly found. But that is very close to Rayne and it's basically just tomb stones in the forest now, because they've been there so long.
Burying a body that deep means the chance of it never being found despite bad weather conditions.
