A mass grave with 210 bodies has been uncovered at the Nasser hospital in southern Gaza by Gaza Civil Defense workers, following the withdrawal of Israeli forces from the area on April 7.

Workers are still searching for the bodies of another 400 missing people after a months-long Israeli offensive left the city of Khan Younis in ruins, a Civil Defense spokesman and head of the search mission, Raed Saqr, told CNN.

A CNN stringer who visited the scene Sunday said people had buried the bodies of family members who had been killed in the grounds of the hospital as a temporary measure.

But, after the Israeli military withdrew, people returned to discover the bodies had been dug up — apparently because the IDF was using DNA testing to see whether any of the hostages held in Gaza were among the dead. The bodies were then placed in at least one collective grave, the stringer said.

One man at the scene told CNN that he has yet to find the body of his 21-year-old son, who was killed in January.

“I haven’t found him yet. We had buried him over there. But we can’t find him. And we wanted to make him a decent grave.”