Follow The Money

I'm shocked if no one else has thought of this. The way to track down the perps is ridiculously simple. Don't go through the front door. Go through the back door by following the money.

Arrange with a pool of private citizens to allow their phones to be tapped. If they get a call from Rachel, their instructions are to order whatever trash Rachel is selling and make payment. Then, follow the money trail the results from the transactions.

Use public funds to cover the volunteers' payments.