The buyers of Clear Channel Communications received a curious e-mail message last July from Credit Suisse, one of the banks financing the radio broadcaster’s sale. But it was misdirected and not meant for their eyes.

Attached to the message were confidential documents from the six banks that had agreed to finance that $19.5 billion takeover. What the prospective buyers, Bain Capital and THL Partners, found most startling was that the banks were discussing how they planned to renege on terms of the lending agreements, just two months after they had reaffirmed their commitment to financing the deal.

That e-mail message has set the stage for a big and complex battle over a broken private equity deal. On Wednesday, Bain and THL filed suits against the bank consortium, naming Citigroup, Morgan Stanley, Deutsche Bank, the Royal Bank of Scotland and Wachovia, as well as Credit Suisse.

In New York on Monday, nearly 30 people from the private equity firms and banks met at the law firm of Ropes & Gray to try to reach an agreement. But the banks refused to finance the deal, according to people involved in the meeting, one of whom described it as “a lot of silent staring and awkward moments.”