Letter to the Editor: Who finances ISIS?

Dear Editor: 

Last week "Frontline" had a program about ISIS. They stated that the people in Afghanistan joined ISIS because they were paid $700 per month, which is a good amount of money in that country. 

But in the whole program, they never stated who paid them this money. Not any news program on TV or newspaper ever states who pays ISIS their salary. 

Is our government keeping this information from us, and if so, why?

Mike Sandoval