JER 40:15

15 Then Johanan the son of Kareah spoke to Gedaliah in Mizpah secretly, saying, Let me go, I pray thee, and I will slay Ishmael the son of Nethaniah, and no man shall know [it] : why should he slay thee, that all the Jews who are gathered to thee should be scattered, and the remnant of Judah perish?