Jeremiah 41:7; Jeremiah 41:9

7 When they went into the city, Ishmael son of Nethaniah and the men who were with him slaughtered them and threw them into a cistern.

9 Now the cistern where he threw all the bodies of the men he had killed along with Gedaliah was the one King Asa had made as part of his defense against Baasha king of Israel. Ishmael son of Nethaniah filled it with the dead.