WASHINGTON — In the winter of 2014, an Afghan with links to top Taliban leaders approached Afghanistan’s intelligence service with a startling tip: Mullah Muhammad Omar, the secretive leader of the Taliban, had died in a hospital in Karachi, Pakistan.
The tip left the intelligence service, the National Directorate of Security, with a mystery that would take 18 months to begin unraveling. But even with the Taliban confirming on Thursday that the man they called Emir al-Momineen, or Commander of the Faithful, was dead, American and Afghan officials said they were just starting to piece together the story of Mullah Omar’s final years and of his demise.