They can loan your club a frequency scanner to aid you in localizing/identifying the source, but the leg work is for you to do. Contact Jose Sota, D-V Frequency Coordinator [link=http://www.amadistrict-v.org/cgi-bin/msb.cgi?9]HERE[/link].
Bear in mind that the operator of an interfering source is not necessarily or even likely to be in violation of the law. An AMA club and members thereof have no superior right to use of the public service frequencies allocated to model airplane control than any other person using them for R/C of a model airplane. Fact is, your rights are diminished because you are obligated to operate per AMA rules (ex: 3 mile separation from known sources of interfering signals); if the interfering operator is non-AMA, he has no obligation to conform to AMA rules. IOW, be nice to him/them and see if you can work out a frequency sharing agreement.

Abel