Last Tuesday, Western Sky suspended operations, saying it was a victim of regulatory overreach, though its affiliate, Cash Call, was still functioning. Katya Jestin, a lawyer at Jenner & Block who represents the companies, said that because Western Sky operated on the Cheyenne River Indian Reservation in Eagle Butte, S.D., New York officials had no jurisdiction over it.

“We will be moving to dismiss the suit against Cash Call and the other parties,” Ms. Jestin said in an interview on Thursday. “Consumers voluntarily entered into the loans and agreed when they signed the loan agreements to be bound by the laws and the courts of the Cheyenne River tribe. The A.G.’s lawsuit is an attempt to sidestep these agreements and is an infringement on the tribe’s inherent sovereign rights and the rights of its members.”

It is unclear what more might happen with the New York attorney general’s case. But here’s a suggestion: When prosecutors pursue payday lenders, why not go further? Investigators should track down — and disclose — the institutions and individuals who make these operations possible by providing the capital that such companies need to conduct their business.

The capital needs of companies like Western Sky are crucial because, unlike banks, they don’t take in deposits that they can turn around and lend. They have to rely on financing from other sources.