There are many theories that claim RJ is Van Pelt.  It is not:

The last ep of season 1, the sheriff and PJ walk into an abandoned house and PJ almost walks into RJ.  He juggles the door handle but the door is locked.  Behind the door, we see a shadow who is shown leaving a table with  cup of tea on it.  The sheriff is the son of RJ's associate and RJ is staying there. 

While this happens, Rigsby and Cho discover the true identity of the sheriff and call Lisbon.  When she doesn't answer, they call Van Pelt who is at the office.

So, RJ is not Van Pelt or any member of the team.