(CNN) -- Lebanese authorities have arrested the wife of ISIS leader Abu Bakr al-Baghdadi -- the man spearheading the Islamist terror group's sweeping rampage across Syria and Iraq -- said a source with knowledge of the arrest, describing her as a "powerful figure (who is) heavily involved in ISIS."
The woman detained is one of al-Baghdadi's two wives. Her arrest came as part of a "planned operation," according to the source.
News agencies Reuters and Agence France-Presse also reported, citing unidentified Lebanese security officials, that one of al-Baghdadi's sons was detained. The detentions took place near Lebanon's border with Syria when they tried to enter the country, according to those reports.
No details were available on the names or nationalities of the son or the woman, nor is it clear how many children al-Baghdadi might have. Lebanese authorities didn't immediately respond to requests for comment from CNN.
And it was unclear when the two were picked up by Lebanese forces -- Reuters said it happened "in recent days," AFP reported it was 10 days ago.
Regardless, the very idea that a government may be holding close relatives of al-Baghdadi is significant, given his pivotal role in ISIS' meteoric rise, the extremist group's widely reviled tactics under his leadership and the breadth of the international coalition aimed at defeating ISIS.
"It's certainly a new dynamic because we've never seen anybody connected so close to al-Baghdadi being detained," terrorism expert Sajjan M. Gohel told CNN.
At the same time, the reports raise a lot of questions, such as what the family members might have been doing in Lebanon.
"Is he estranged from them? Has he fallen out with them? Were they escaping from him?" asked Gohel, who is the international security director at the Asia Pacific Foundation.
As to how Lebanon got mixed up in all this, it's one of several countries heavily affected by Syria's years-long conflict and the flood of refugees trying to escape the violence.
Lebanese authorities "have been cracking down very heavily on the border to prevent members of ISIS seeping into Lebanon," Gohel said. "They don't want the problems spilling over from Iraq and Syria into their territory."
ISIS rises after al-Baghdadi took over
The group that, in 2006, would become ISIS began in Iraq, where it targeted the U.S.-led coalition as well as Shiite Muslims in the country.
It suffered heavy losses, but ascended over the past few years to take advantage of a void wrought by Syria's civil war as well as instability in Iraq.
Not coincidentally, this all happened after al-Baghdadi took over ISIS in 2010, not long after his release from a U.S. prison camp for insurgents at Bucca in southern Iraq. He had been taken into custody during fighting in February 2004 in the flashpoint city of Falluja and spent four years at the prison camp, almost certainly developing a network of contacts and honing his ideology.
Beyond this, little is known about al-Baghdadi. According to the U.S. government, he was born in Samarra, Iraq, and is in his early 40s. But what motivates him, how he was trained and who he's close to -- including his family -- largely remains a mystery.
Yet he has emerged from the shadows in fits and spurts.
After the death of al Qaeda leader Osama bin Laden in 2011, al-Baghdadi issued a eulogy in which he threatened violent retribution. (Al Qaeda disowned ISIS earlier this year, blaming it for "the enormity of the disaster that afflicted" others trying to unseat Syrian President Bashar al-Assad.)
There were unconfirmed suggestions last month that al-Baghdadi had been wounded in airstrikes in northern Iraq.
But days later, an audio recording emerged that purportedly contained a message from al-Baghdadi saying the U.S.-led coalition to destroy ISIS is "terrified, weak and powerless."
'He's created this myth'
ISIS itself has never been more powerful, having taken over vast swaths of territory in Iraq and Syria in the past few years. And it has used brutal tactics to do so -- such as mass kidnappings, rapes, killings and other abuses against civilians and fighting foes alike, actions that a U.N. panel characterized as war crimes and crimes against humanity.
And Al-Baghdadi, who has gone by a variety of aliases during his career in terrorism, has been at the center of it. The U.S. State Department's Reward's for Justice program, which refers to him as "Abu Du'a," offers $10 million for information leading to his arrest.
When his group rebranded itself as the Islamic State in June, al-Baghdadi was tapped as spiritual leader of the new caliphate.
He's sought to burnish his theological credentials, with a biography posted on jihadist websites last year claiming he had earned a doctorate in Islamic studies from a university in Baghdad.
"His knowledge in Islamic jurisprudence is somewhat dubious, but nevertheless he's created this myth and this aura behind him," Gohel said.
CNN's Elwazer Schams contributed to this report.