It had been nearly a month since the Philadelphia District Attorney's Office said it would vacate the conviction of Shaurn Thomas—who was incarcerated for more than 20 years, and the first defendant to have his conviction overturned under a newly revamped conviction review unit in the prosecutors' office. But the atmosphere Tuesday morning in Philadelphia Court of Common Pleas Judge Rose Marie DeFino-Nastasi's packed courtroom was tense.

Neither Thomas, who had been out of jail since mid-May, nor his attorneys—Marissa Boyers Bluestine, legal director for the Pennsylvania Innocence Project, and James Figorski of Dechert—knew whether the prosecutors planned to reinstate the charges against him, and have Thomas, now 43, retried in the 1990 murder case that already led him to spend his adult life in prison.

Thomas had been 16 when Domingo Martinez was hit by a car and then shot to death through his front windshield as he was driving to deliver $25,000 to a check cashing store he owned, according to the Pennsylvania Innocence Project. In 1994, Thomas, then 20, was convicted for murder and sentenced to life without parole.