"That's a good question, " Assistant District Attorney John O'Mara, who heads the district attorney's Conviction IntegrityUnit, said after a judge released Ranta.
The decision to look into the Patz case is one of several campaign promises Mr. Vance has fulfilled since taking office in January, including creating a conviction-integrity unit.
Prosecutors have determined the evidence underpinning Ranta's conviction "has been degraded to such an extent" that it would no longer support the verdict, said John O'Mara, the deputy district attorney in charge of Brooklyn's conviction integrityunit.
Hanging over the Edwards case was the specter of the Stevens case, where the department's public integrityunit suffered a major loss in 2009, when Attorney General Eric Holder asked a judge to dismiss the conviction of Mr. Stevens because of prosecutor misconduct.