A New York City man who spent 20 years in prison for a killing he says happened while he was in Florida has asked a judge to keep his case open so he can be fully vindicated.

Richard Rosario's unusual request came Friday after prosecutors said they were ready to drop charges but stopped short of fully exonerating him.

The judge agreed to leave the case open through at least Aug. 30.

The 40-year-old Rosario was freed in March, when prosecutors agreed he had been wrongfully convicted in the 1996 killing of Jorge Collazo, also called George.

Rosario said he had given authorities the names of 13 people who saw him in Florida. Two testified at his trial. His lawyers didn't send an investigator to Florida to speak to others.