What happened to them after their release proved even more problematic. As exonerees, they emerged with big dollar signs on their backs. Most states compensate the wrongfully imprisoned in amounts that can reach millions of dollars, and exonerees can also win settlements from police agencies — awards that can attract predators.

Mr. McCollum, 54, and Mr. Brown, 50, proved virtually helpless as hundreds of thousands of dollars of state compensation were siphoned off by their supposed protectors: a sister back home; a lawyer from Orlando, Fla.; a self-proclaimed advocate from Atlanta, and her so-called business partner, a college instructor from Brooklyn, according to documents and interviews by The Marshall Project.

By the time a federal judge intervened in the spring of 2017, no trust had been set up for the brothers and money intended for their care had been spent on predatory loans, exorbitant legal fees, multiple cars, women’s jewelry and children’s toys.

Jeffrey Deskovic, an exoneree who established a foundation to help the wrongfully convicted, said he had advised about 60 other exonerees on how to manage compensation and the unwanted attention it brings. The experiences of Mr. McCollum and Mr. Brown are extreme, he said, but the underlying dynamics are common.

“All were hit up for money by family and friends or were targets of scammers,” Mr. Deskovic said.

The brothers’ tragic story began decades earlier. Schools had identified Henry McCollum and Leon Brown as mentally challenged: Mr. McCollum read at a second-grade level when he dropped out of high school; his younger brother could barely read or write.