For the Tehrik-e Taliban Pakistan (TTP), the issue of succession has always proved divisive and often bloody.
So it might prove again for the TTP following the death of charismatic and ruthless leader Hakimullah Mehsud, who was killed in a suspected U.S. drone attack in Pakistan's Federally Administered Tribal Areas (FATA) on November 1.
Days of secret meetings and discussions have yielded an interim leader, Asmatullah Shaheen Bhittani, the current head of the TTP's shura, or council. But Bhittani is widely considered to be merely a short-term fix until a permanent leader can be named.
With a decision looming, an internal struggle for power can be expected among the several prominent factions within the umbrella militant group, some of which have a history of bad blood between them.
According to Michael Kugelman, South Asia associate at the Woodrow Wilson International Center for Scholars in Washington, internal divisions within the TTP have often led to violence.
"Succession has always been a problematic issue for this organization just because it's a very fractured group with a lot of divisions that tend to play out violently," he says. "So, it's always been difficult for them to settle on a successor."
Kugelman says that Hakimullah Mehsud established an iron grip on the TTP that helped contain factional infighting. But with him gone, those differences could boil over.
In 2009, when former leader Baitullah Mehsud was killed in a suspected U.S. drone attack, it took weeks of heated discussions and even gunfights before the TTP could settle on a successor.
Now, with the shura again preparing to select a new leader, we look at some of the names that are believed to be under consideration.
Khan 'Sajna' Said
The favorite to assume the leadership is the TTP's former deputy leader Khan Said, also known as 'Sajna'. The 36-year-old Said, who early on was reported as a nominee to succeed Hakimullah Mehsud, is the leader of the South Waziristan wing of the TTP.
He had a close relationship with Waliur Rehman Mehsud, the former deputy leader of the TTP who was killed in a U.S. drone attack in May. Said has indicated his support for peace talks with the Pakistani government. While some reports have labeled him a relative moderate, others have painted him as a ruthless fighter and ideological fanatic.
Said is believed to have strong support in North and South Waziristan, the birthplace and headquarters of the TTP. He is also from the Mehsud tribe, which dominates top positions in the TTP.
Said is believed to have friendly relations with the Afghan Taliban and the Haqqani Network, an Al-Qaeda-affiliated terrorist group that fights against Afghan and international forces across the border in Afghanistan.
Shuja Nawaz, director of the South Asia Center at the Atlantic Council of the United States in Washington, sees Said as the most viable candidate for the leadership.
"Going back to someone who is from South Waziristan and who belongs to the Mehsud tribe may clear difficulties with some of the TTP's far-flung operations, which are under local commanders," he says. "Somebody who is prepared to talk without preconditions would also be preferred."
Shahriyar Mehsud is a little-known TTP fighter. He was expelled by former leader Baitullah Mehsud from North Waziristan. He is reported to have lived in Afghanistan before returning to North Waziristan after Baitullah Mehsud's death in 2009.
Shahriyar Mehsud was close to Hakimullah Mehsud but he never assumed a senior position within the group. Since Hakimullah Mehsud's death, his faction has publicly backed Shahriyar Mehsud. But his inexperience and lack of influence makes him an outside bet to become the new leader of the TTP.
There is bad blood between Hakimullah Mehsud's camp and Said, who was deposed as deputy leader of the group earlier this year by the former leader. The point of contention between them reportedly was the issue of peace talks with the Pakistani government. Hakimullah Mehsud was known to be against any dialogue with the government.
Omar Khalid Khurasani
Khurasani is the leader of the TTP's wing in FATA's Mohmand Agency. He is considered to be one of the TTP's most effective and powerful leaders. Khurasani, who real name is Abdul Wali, belongs to the Safi Pashtun tribe.
He rose to prominence when he seized a Sufi shrine in Mohmand and renamed it in honor of Islamabad's radical Red Mosque, which was the scene of a deadly weeklong battle between radical students and Pakistani security forces in 2007.
Khurusani, who is believed to have close ties to Al-Qaeda, has fought in Kashmir, the Himalayan region disputed by Pakistan and India. Despite his influence within the TTP, Khurusani is considered an unlikely successor because he does not hail from the Mehsud tribe.
Fazlullah is the head of the TTP's wing in Swat Valley. His forces infiltrated Swat in 2007 and enforced draconian rules similar to those imposed by the Afghan Taliban. Men were forced to grow beards, women were discouraged from venturing outside, and schools were destroyed. A military offensive by the Pakistani army pushed most of Fazlullah's forces out of Swat in 2009. He is believed to be residing across the border in eastern Afghanistan.
His group still has a presence in Swat, however. His forces are believed to have carried out the shooting of schoolgirl and education campaigner Malala Yousafzai last year.