Then why not pick a few people off leaving Synogogues and Hindu temples?
Maybe the shots are crappy, or due to zoning they tend to be clustered around other churches and have to many people around them. Or the terrorist angle is wrong (which bodes ill for RKBA issues).
Be interesting to see how this phone number bit pans out. I can't believe the guy[s] would be stupid enough to call a number he\they left. Maybe when this was initially in local LEO's hands it would be remotely possible to attempt it but now there will be so much tracing and ELINT on that call people with pace makers in the area will grow younger.
The first rule of anyone who knows how to hack or phreak (phreaking being phone system hacks) is to NEVER attract the attention of the Feds because they have infinite resources and time to devote to catching you and you will get caught. If the call is made, they will be caught...