A factional leader of Boko Haram loyal to Islamic State in West Africa (ISWA), Mamman Nur, has been killed by his fighters who rebelled against him.

Nur, the brain behind the ties between Boko Haram and the Abu Bakr al-Baghdadi led Islamic State, was said to have been killed by his closest lieutenants on August 21, for releasing the Dapchi girls, without demanding ransom, among other reasons.

In 2014, Nur led the rebellion against Abubakar Shekau, which saw the emergence of Abu Mus’ab Al-Barnawy faction of the group.

The breakaway faction, which moved to shores of Lake Chad region in Northern Borno, was later recognised by the Al-Baghdadi.

The new leader Al-Barnawy, whose real name is Habib, is the son of Boko Haram founder Mohammed Yusuf, who was killed in 2009.

A source, who spoke to Daily Trust, said: “Mamman Nur, who was killed on August 21, is the actual leader of the Boko Haram faction after they parted ways with Shekau. He (Nur) only put Habib in the front as shadow leader because of his father (Mohammed Yusuf).

“The name Al-Barnawy is only being heard as symbolic leader; he was meant to lead so that followers would remain committed to the cause championed by his late father but he (Nur) is the major link of the faction with the Islamic State; the chief strategist around Lake Chad, including their cells in Nigeria, Niger and Chad."

Another source told the newspaper that Mamman Nur was killed after long period of disagreement with his subordinates who established “relative authority and contacts” over the years.

“The commanders became disenchanted with Nur’s style of leadership; they saw him as not as rough as Shekau.

“They followed him in staging the revolt because the argument back in 2014 was that Shekau was a hardliner who killed almost everyone, both Muslims and Christians who disagreed with his brand of Islam.

“But according to some of the fighters, after establishing his base in Lake Chad, Mamman Nur too ‘deviated from the real course’ and compromised on so many occasions,” he said.

He said a major disagreement broke after the release of the some 100 girls abducted in a secondary school in Dapchi, Yobe State, in March.

The source continued: “The negotiation of the release of the girls did not go down well with some close associates of Mamman Nur who released the girls unconditionally, following a directive by Al-Baghdadi.

“Nothing was paid before the girls were released and besides, Mamman Nur’s soft approach and close contact to governments and different levels angered his foot soldiers who rebelled against him and thereafter executed him."

It was learnt that Al-Barnawy had also lost firm control of the group which is now under the “guidance” of a certain commander.

“The man in charge of all the cells in the Lake Chad region is the former commander of the fighters who was directly under the control of late Mamman Nur,” he said.

A security expert, Major Salihu Bakari, told the paper that the upsurge in Boko Haram attacks in Northern Borno could be related to the change of leadership.

“The truth is Mamman Nur had lost control long before he was killed; the factional group was taken over by hardliners who share a lot in common with the Shekau faction whose landmarks include kidnapping, assault, abductions for ransom and other atrocities,” he said.

He said the new group had recently attacked many army facilities in northern Borno and also captured individuals for ransom.

“They want ransom to continue financing their activities; I think their demands for high ransom is what is delaying the release of many abductees, including the female health workers that were captured in Rann in Kala-Balge Local Government Area of Borno State,” he said.

The Nigerian military has yet to confirm the killing of Mamman Nur.

However, on January 6, the military said Nur's wife was killed when troops attacked the group’s location in the Lake Chad region.

The spokesman of the Operation Lafiya Dole Theatre Command in Maiduguri, Onyema Nwachukwu, said at the time that about 250 Boko Haram fighters on the side of Mamman Nur had surrendered.

The announcement came hours after the military declared Nur as “fatally injured” during an operation.

In September 2011, the Department of State Services (DSS) placed a N25 million bounty on Mamman Nur, a close ally of Mohamed Yusuf and Shekau, who was accused of masterminding the bombing of the UN building in Abuja.