Khalil Ibrahim, or Dr. Khalil as he is widely known, is the most wanted man in Sudan, with a bounty of some $250,000 on his head. He came to prominence as a member of the National Islamic Front that brought President Omar al-Bashir to power in 1989, holding a number of regional government posts in the 1990s and helping to conduct the military effort against rebels in southern Sudan.
He was a follower of Hassan al-Turabi, the main Islamic ideologue behind the regime. But both Khalil and Turabi broke with the government in the late 1990s. Khalil went on to form the Justice and Equality Movement, or JEM, which along with the Sudan Liberation Army, has become one of the main rebel forces in the western Darfur region.
Khalil is still suspected by some of ties to Turabi, and the latter was one of the first to be detained in the security sweeps following Saturday's attack. But both Turabi and Khalil have denied continued cooperation, and Turabi was quickly released for lack of evidence. Still, some analysts say the role of JEM should be seen in terms of an ongoing power struggle within the Islamic movement.
"To me there are three wings to the Islamic movement, the NCP which is the ruling party, Turabi's party which is the Popular Congress Party, the JEM, the Justice and Equality Movement," says Munzoul Assal, a professor of anthropology at the University of Khartoum.
So in a way this is more or less a struggle within one body which used to be the Islamic movement and it's taking a very ugly shape."
While Khalil maintains his support for political Islam, the group has come to be seen as primarily a regional movement. Though, as Assal says, Khalil has attempted to promote a more national agenda, addressing regional inequalities throughout Sudan.
"One thing that is clear about Khalil is that he is very ambitious as a political leader and he is looking far beyond Darfur and he has always been saying that our problem is not Darfur, our problem is just sharing and distribution of wealth and political power in the country," he says.
The recent attack has been interpreted by many as an attempt to turn the Darfur conflict into a national one, by bringing the fighting to the capital, which so far remained insulated from Sudan's years of civil war.
But despite Khalil's ambitions, analysts say JEM remains a movement with a very narrow ethnic base. Even within Darfur, it is dominated by members of the Kobe subgroup of the Zaghawa tribe.
"I believe JEM has proved to be a clearly Darfurian movement but it has also a handicap in Darfur," says researcher Jerome Tubiana, who is the author of a recent Small Arms Survey report on Darfur's rebel groups.
"It's leaders in particular, and also its soldiers, are mostly drawn from a very small Zaghawa subgroup straddling the Chad-Sudan border. And this is a problem. And will still be a problem in the years to come, if JEM really intends to play a political role inside the whole Sudan."
With its ethnic ties to neighboring Chad, JEM has been the main beneficiary of Chadian support for Darfur's rebels. Both Chad and Sudan have supported rebel groups targeting the other government, and Chadian rebels backed by Khartoum launched an attack on the capital N'Djamena in February. President Bashir swiftly blamed Chad for the recent attack on Khartoum and cut diplomatic relations.
Tubiana says Khalil's relations with Chad's president Idriss Déby have in fact been strained since the February attack, when Khalil was seen as not doing enough to defend the Chadian government. But he says that even without support from Déby himself, Khalil likely received backing from other elements within the Chadian regime.
"The fact is that relations between Dr. Khalil and President Deby have never been really good," he says. "But inside the Chadian regime, including inside the family of President Déby, some people have always been supportive of JEM. Even if the relations between Déby and the JEM were pretty cold in the last month, I would say Déby is just unable to prevent his kin and his family from supporting the JEM.
Support from Chad is a main reason JEM has become, militarily, the most powerful faction on the ground in Darfur. But efforts by JEM to broaden its political base have been largely unsuccessful. And relations with other rebel groups - particularly the several factions of the Sudan Liberation Army - remain tense. Some of the other rebel leaders voiced support for JEM's recent attack, but it appears that there was little active coordination.