As an array of local and international forces close in on Islamic State’s last redoubts in Syria and Iraq, the whereabouts of the extremist group’s secretive leader remain a mystery.

A media outlet linked to the Syrian military reported Friday that Abu Bakr Baghdadi had been spotted in the eastern town of Bukamal during a recent offensive to recapture Islamic State’s last urban stronghold in Syria. But Baghdadi sightings have been reported before. So has his death. None of it has ever been confirmed.