Even with a $25 million State Department bounty on his head, Baghdadi has managed to avoid detection from the US coalition, which worked with Syrian Democratic Forces to retake Raqqa.
A month later, Townsend's skepticism was validated when a 45-minute audio recording surfaced of the ISIS leader mocking the United States, rallying remaining jihadis against the Syrian regime and insisting that ISIS "remains," despite mounting casualties and the loss of large swaths of its territory.
US officials previously indicated they believe Baghdadi is hiding somewhere in the Euphrates River Valley, now the last strip of ISIS' territory. It crosses the border of Syria and Iraq.
The United States over the summer believed it had an opportunity to kill Baghdadi in an airstrike and "tried to take several shots" at him, according to officials who spoke to CNN. But the self-professed caliph's death was never confirmed.
CNN's Dominique van Heerden and Barbara Starr contributed to