Heller said that
there is a clue in the last minutes of 06x01 which would be clear in later
episodes. 


The clue is the GPS Mobile tracker in which you can see the initials for the 7 suspects. Kirkland is in
LA(K) - so could not be him. S1(maybe Stiles) is far away in San Franscisco and static,
S2(maybe Smith far away but in transit). The
closest to Patridge(P) are Bertram(B - static) and Haffner (H - in transit). You can also their addresses. 


Now
some opinions. It's the moment when Lisbon is watching on the computer and
being called.