The Camden County Prosecutor's Office said people walking in Gloucester Township discovered the grave April 20.
The grave was marked with a small cross, a stuffed animal, flowers and a statue of a cherub, The Philadelphia Inquirer reported Thursday. Investigators said items left at the grave indicate it is that of a small child or infant.
Investigators exhumed the grave, finding a cardboard box holding a Ziploc bag filled with cremated remains. The bag was labeled with a female name, though authorities have not found a death certificate and no area crematoriums have records matching the name, the newspaper said.
Investigators, who have not released the name, left a note at the site of the grave asking family members to come forward and provide a death certificate so the remains can be properly buried.