Jeremiah 41:2

41:2 Ishmael son of Nethaniah and the ten men who were with him stood up, pulled out their swords, and killed Gedaliah, the son of Ahikam and grandson of Shaphan. Thus Ishmael killed the man that the king of Babylon had appointed to govern the country.

Jeremiah 41:10

41:10 Then Ishmael took captive all the people who were still left alive in Mizpah. This included the royal princesses and all the rest of the people in Mizpah that Nebuzaradan, the captain of the royal guard, had put under the authority of Gedaliah son of Ahikam. Ishmael son of Nethaniah took all these people captive and set out to cross over to the Ammonites.