Cameron isn't there to do it. Derek and Sarah are more likely to break the computer than use it to track the signal.Gee. If only there was some way we could track down the signal!
... Call the poilice?
Most likely Michelle would be killed in the process. A cop would have little chance against Cromartie - an FBI SRT didn't.
You also take the chance that they may manage to disable Cromartie. If that would happen he could potentially be used to hasten the arrival of JD.