The Taliban, bane of America's post-9/11 Afghanistan operations, said Wednesday that they captured Mullah Abdul Rauf Khadim, a renegade insurgent and ex-Guantanamo detainee who was in Afghanistan recruiting for the Islamic State, the latest parry in a messy internecine conflict between violent Islamist regimes.

The independent Pajhwok news agency of Afghanistan reports that Khadim—who had previously been identified in the media as an ex-Taliban footsoldier who sought revenge against the U.S. after his detention in Gitmo—was arrested, along with 45 armed followers, after attempting to turn local militants against the Taliban and win their allegiance for ISIS's attempts to build a global caliphate:

A tribal elder in Kajaki, Abdul Ahad Masoomi, also a member of the provincial reform committee, told Pajhwok Afghan News that harsh differences had recently surfaced between local militants and Mullah Abdul Rauf Khadim group.

"Mullah Khadim, who claims allegiance to Daesh (Arabic acronym for IS) forcibly assembled local residents on Thursday last in the Kakaji's Azan area and told the people that Mullah Omar no longer exists and they should now support him."

...A senior official in Helmand said Mullah Rauf had been one of Mullah Omar's close aides. He was detained during Taliban's last year in power in northern Afghanistan and was handed over to the US.

Rauf's work was the latest in an ambitious expansion program that ISIS has reportedly pursued ever since consolidating its power in a large area of Syria and Iraq. Many former Al Qaeda militants have pledged fealty to the new jihadis on the block, and reports even suggest ISIS has approached Ayman al-Zawahiri, Osama bin Laden's successor as the nominal Al Qaeda leader, to renounce the Taliban in Afghanistan and back ISIS as the future of Islamic governance.

But Rauf, 33, is an especially interesting character. He spent seven years in Guantanamo Bay as Prisoner No. 108 and was released by the U.S. into Afghan custody in 2007. According to documents released by Wikileaks, Rauf was designated a "medium" risk and slated for transfer out of Guantanamo as early as 2004. Analysts said Rauf had admitted to involvement with the Taliban's illicit opium trade and identified him as one of "two cell block leaders attempting to instigate and influence the rest of the cell blocks to disregard orders, make noise, refuse food, and commit suicide."

One analyst added in Rauf's record: "For a simple Taliban foot soldier and bread deliverer, detainee manages to exhibit leadership qualities by conducting speeches and instilling fear into those who cooperate with [U.S.] personnel."

A later Newsweek report, however, suggests that Rauf had been more than a footsoldier: He was identified as the head of "Mullah Omar's elite mobile reserve force, fighting regime opponents all over Afghanistan." About a year after the U.S. repatriated him to Afghanistan, Rauf escaped from house arrest and emerged to terrorize Afghans who had cooperated with the U.S.-led coalition. "He will be very important in the future," a Taliban commander said of him in 2011.

On Wednesday, a Taliban commander told Pajhwok that the fate of Rauf and his army "would be decided by Taliban religious leaders and judges." Then again, the Taliban likely can't be trusted to give a fair assessment of ISIS's strength in Afghanistan. Two weeks ago, they were claiming Rauf was their friend.

"We know Mullah Abdul Rauf Khadim," one Talib leader told the New York Times in mid-January. "He was a member of the Taliban, but now he is sitting at home."