Jalaluddin Haqqani, the Afghan founder of the militant Haqqani network, died at least a year ago, sources close to the group have told the BBC.
Haqqani died after a long illness and was buried in Afghanistan, the sources added.
Rumours about Haqqani's death have circulated for some years and the group has still not confirmed the reports.
The network has been behind many of the co-ordinated attacks on Afghan and Nato forces in recent years.
Haqqani's son, Sirajuddin Haqqani, has long been thought to be in de facto control of the organisation.
The network has links to al-Qaeda and to the Taliban.
Jalaluddin Haqqani was an Afghan guerrilla leader who fought Soviet troops that occupied Afghanistan in 1980s.
US officials have admitted that at the time he was a prized asset of the Central Intelligence Agency (CIA).
However, he later allied himself to the Taliban after they took power in Afghanistan in 1996. Haqqani served as a cabinet minister under the Taliban's supreme leader, Mullah Omar.