Answer: Nebuchadnezzar, king of Babylon
Judah had been paying tribute to Babylon for many years. When King Jehoiakim refused to continue paying the tribute, the king of Babylon laid siege to Jerusalem for many years and finally took the city.
The king of Babylon plundered the city and the temple and took most of the inhabitants to Babylon as slaves.
The captivity of the Jews lasted 70 years until Cyrus the Persian conquered Babylon and allowed the Jewish captives to return to Jerusalem.