Who are the top terrorists still at large?

The Afghan government says Taliban leader Mullah Omar is dead.

But several key terror figures are still at large. Here are some of the world's most wanted terrorists.
Ayman al-Zawahiri is the current commander of Al-Qaeda. He was Osama bin Laden's right-hand man and the group's operational leader. Some think he had a bigger role planning the 9/11 attacks than his boss.

Today, his group is fighting ISIS for supremacy, which he cut ties with in 2014. As for Zawahiri, it's believed he's hiding out somewhere in Pakistan's tribal areas.

As the head of ISIS, Abu Bakr al-Baghdadi considers himself the leader of the world's Muslims and his so-called caliphate. Little is known about Baghdadi. In fact, Baghdadi isn't even his real name.
Earlier this year, there were rumors he had been killed in an airstrike.

But in May, the reclusive leader released an audio recording, calling on Muslims to pledge allegiance to ISIS.

See photos of the terrorists:

Abubakr Shekau is the leader of Boko Haram. For the past six years, his group has terrorized Nigeria with a wave of bombings and mass kidnappings.

Shekau has pledged allegiance to Baghdadi — making Boko Haram one of ISIS' biggest affiliates.
Shekau's exact whereabouts are unknown. The Nigerian military has claimed to have killed him before, but he always resurfaces in propaganda videos like this one.

Ibrahim al-Asiri is Al-Qaeda's master bomb-maker and a prominent figure in its Yemen-based affiliate, Al-Qaeda in the Arabian Peninsula or AQAP.

The Saudi chemist was likely behind the underwear bomb a Nigerian terrorist smuggled onto a U.S. airliner in 2009.