Gilson, who has spent 27 years with the city District Attorney's Office, will work closely with prosecutors assigned to the existing Post Conviction Relief Unit, which currently handles about 500 cases a year. Of those cases, just three or four result in relief for convicted people, such as new trials, Williams said.
"This is an opportunity," said Gilson, 54, "to take all my experience, all my contacts, and now apply it to those cases in this office where people are in prison - some for life, some on death row - and make sure we got it right."
Williams joins a growing number of district attorneys across the country who have created similar conviction-review units. Possibly the most heralded is in Brooklyn, N.Y., where reinvestigations launched by new District Attorney Kenneth Thompson have resulted in three overturned murder convictions since January.
Marissa Bluestine, legal director of the Pennsylvania Innocence Project, applauded Williams' new unit.
"We are looking forward to working with Mr. Gilson and his staff to give full evaluation to those cases where there is a colorable claim of actual innocence," said Bluestine, whose Philadelphia-based nonprofit has petitioned city prosecutors to reopen 10 cases in the last three years.
One is that of Lance Felder, 35, and Eugene Gilyard, 34, who spent 15 years in state prison, doing life without parole for a 1995 murder, before a judge tossed their convictions in October and ruled that they should get new trials.
Bluestine's organization uncovered evidence that two other men - including a man already in prison - committed the murder for which Felder and Gilyard were convicted.
On Twitter: @MensahDean