Washington(CNN) A new theory on the whereabouts of ISIS leader Abu Bakr Al-Bagdadi is emerging, according to nearly half a dozen U.S. officials CNN has spoken with across several government departments.
While it's still possible that the U.S.'s most wanted man continues to be hunkered down inside the self-declared ISIS capitol of Raqqa, Syria, a more recent analysis potentially puts Baghdadi in constant motion as he attempts to avoid being killed or captured by anti-ISIS coalition forces.
"We have no reason to believe that Baghdadi's not still alive, but we have not heard from him since the end of last year," U.S. Special Envoy Brett McGurk said Friday, referring to an audio tape that surfaced online in December.
U.S. officials agree on two initial points. First, they don't know exactly where he is, and if they did, they would attack his location either from the ground or air if they could.
Second, Baghdadi is practicing, in the words of one official, "extraordinary operational security" to keep his location secret.
For months, the general theory has been that he's hiding in one of several buildings in or near the center of Raqqa. In fact, officials have described to CNN one potential target: a building that they believe at some point had a jail inside of it.
Officials also have long thought Baghdadi, like other ISIS leaders, chose the densely populated areas of central Raqqa as a hideout, believing the U.S. would not risk killing large numbers of civilians with an airstrike against him.
Raqqa for months has been under firm ISIS control with no nearby opposition forces. That may have led to the calculation by Baghdadi that the U.S. would not risk a ground-based "capture or kill" mission similar to the raid on Osama bin Laden by Special Operations forces in Pakistan in 2011, so deep into ISIS territory.
The possibility that Baghdadi is hiding in Raqqa has in no way been dismissed.
However, officials say the alternative scenario -- that Baghdadi is moving around -- is actively being considered. There was intelligence believed to be credible over the last six months that Baghdadi traveled to the Mosul, Iraq, area at least twice, a second U.S. official tells CNN. CNN's understanding is the information was not timely enough to launch an airstrike or capture mission, but it has now led in part to government analysts considering the notion he is moving around nearly constantly.
One of the main reasons this theory is being considered is that after "mapping out" the network of top ISIS leaders and killing several of them, there has been no direct information leading from them back to the ISIS leader, officials said.
They all acknowledged that if there was a solid lead on his whereabouts, they would not tell a reporter. But the U.S. has openly dismissed several recent reports that Baghdadi has been wounded in military operations.
Typically, the killing of at least some of the senior ISIS leadership might have led other ISIS operatives to move around, communicate or somehow reveal a lead on Baghdadi's whereabouts. That has not happened, by all accounts.
For example, two top leaders were killed in March in U.S. strikes: Abd al-Rahman Mustafa al-Qaduli, described as al Qaeda's top financier, and Omar "the Chechen" Al Shishani, one of the group's most senior military commanders. Both men would likely have had contact with Baghdadi, officials said, yet since the strikes, there have been no firm clues that have led back to the ISIS leader.
One of the most notable confirmed sightings of Baghdadi came during the holy month of Ramadan two years ago when he gave a sermon at a mosque in Mosul. The U.S. will be keeping an exceptionally close eye with overhead surveillance during the month of Ramadan this year in case Baghdadi decides to emerge and speak publicly, several other U.S. officials said.
"It is Ramadan. He purports to be the caliph -- that's what he calls himself -- and so you would think he'd be coming out with a statement to his -- to his so-called followers," McGurk said.
Whether he is holed up in some location away from the constant eye of U.S. surveillance or on the move, attempting to stay one step ahead of the hunt, the ISIS leader with a $25 million bounty on his head can hardly be careful enough.