When we first reported on the federal probe into Los Angeles Dodgers owner Mark Walter over the weekend, many asked what sparked the government's interest. Our reporters map out the web of hidden deals that caught the feds' attention. Walter's big squeeze also reflects risks in an opaque corner of Wall Street where some of the financial world's titans make large and poorly understood bets.\n\nMark Walter stunned the sports world in 2012 with a deal that left his wealthy rivals wondering how the chief executive of Guggenheim Partners, little-known outside Wall Street, had funded the purchase of the Los Angeles Dodgers, one of the premier teams in Major League Baseball. Few moguls can now claim they aren't familiar with Walter and his international sports kingdom, which included the Los Angeles Lakers.\n\nHis playbook, using loans from insurance companies he controls to finance his other investments, is now under government scrutiny.

Facing pressure from investigators and regulators, the billionaire is racing to unwind bets and save his sports-and-finance empire, report Justin Baer, Margot Patrick, Joe Wallace and Andrew Beaton.