A mentally disabled Louisiana man walked free last week after 20 years in prison for a killing his attorneys say he didn't commit. New Orleans reporter Janet McConnaughey learned that his plea agreement blames him for obstructing justice by falsely confessing to the crime.

Corey Williams was a 16-year-old who still sucked his thumb, often wet himself and had been hospitalized for extreme lead poisoning when Shreveport, Louisiana, police brought him in for questioning in 1998 about a shooting that killed a pizza deliveryman.

For hours, he said he was innocent. Finally, Williams told police he did it and wanted to go home and lie down.

Two decades later, with doubts swirling around his murder conviction and the case submitted to the U.S. Supreme Court for review, Williams accepted a plea agreement, pleading guilty to manslaughter and obstructing justice. That short-circuited a potentially lengthy Supreme Court review. Williams’ murder conviction was vacated and he was sentenced to 20 years for manslaughter, receiving credit for time served. But the district attorney's office said he also received a suspended seven-year sentence for obstructing justice, putting Williams on supervised probation for three years.

South Regional Desk editor Mike Warren asked what the obstruction charge was about. Could it be the confession? Neither Williams’ lawyers nor prosecutors had said.

McConnaughey asked the Caddo Parish District Attorney’s Office for documentation outlining the factual basis of the plea deal. There it was: Williams said he’d obstructed justice by removing evidence from the crime scene and by providing “a false inculpatory statement to police." Williams’ signature was in inch-high printing, with big circles over the i’s.

McConnaughey’s story received strong use by AP customers, including The Washington Post, which had written two previous pieces about the case with multiple bylines but used AP’s story about the plea deal instead.

For pursuing the underlying details and shining a light on a deal that set Williams free – but only after putting the blame on himself for a false confession – McConnaughey wins this week’s Best of the State award.