Jeremiah 41:7; Jeremiah 41:9

7 Yet it turned out that as soon as they came inside the city, Ishmael the son of Nethaniah and the men that were with him slaughtered them and cast them into the cistern.

9 Now as for the cistern where Ishmael had cast all the corpses of the men whom he had struck down because of Gedaliah, it was the one that King Asa had made on account of Baasha, king of Israel; Ishmael the son of Nethaniah filled it with the slain.