Federal charges against the Southern Poverty Law Center's former chief financial officer could open up a much wider case, bad news for the group's leadership.

• The former CFO has been charged, and prosecutors now have someone who knows where every dollar went.
• A finance chief can point to who signed off on what, including approvals from the top.
• Paper trails like internal emails are the usual way these cases climb the org chart.
• The charges feed a broader push to scrutinize how big advocacy nonprofits spend their money.

Outlook: Expect this to widen beyond one person if investigators follow the approval chain upward.