Baghdadi, an Iraqi whose real name is Ibrahim al-Samarrai, is moving in a remote, mostly-desert stretch populated exclusively by Sunni Arab tribes north of the Euphrates river, according to Hashimi.
The area stretches from the town of Baaj, in northwestern Iraq, to the Syrian border town of Albu Kamal on the Euphrates.
"It's their historic region, they know the people there and the terrain; food, water and gasoline are easy to get, spies are easier to spot" than in crowded areas, he said.
The US government has had a joint task force to track down Baghdadi which includes special operations forces, the CIA and other US intelligence agencies as well as spy satellites of the National Geospatial Intelligence Agency.
But Baghdadi seems to have learnt the lessons from the 2011 capture and killing of Osama bin Ladin, and relies on multiple couriers and not just one, unlike the al Qaeda founder, say US intelligence sources.
He also switches cars during trips, a lesson learnt from the 2011 drone strike that killed Anwar al-Awlaki, an al Qaeda figure in Yemen.
Baghdadi has not publicly appointed a successor, but Iyad al-Obaidi, also known as Fadel Haifa, a security officer under former dictator Saddam Hussein, is known to be the de facto deputy, according to Iraqi intelligence sources.