Jeremiah 40:14-15

14They said to him, “Are you at all aware that King Baalis of Ammon has sent Ishmael son of Nethaniah to kill you?” But Gedaliah son of Ahikam would not believe them.

15Then Johanan son of Kareah spoke privately to Gedaliah there at Mizpah, “Let me go and kill Ishmael the son of Nethaniah before anyone knows about it. Otherwise he will kill you and all the Judeans who have rallied around you will be scattered. Then what remains of Judah will disappear.”