ISTANBUL — For a year now, there has been a civil war within the civil war in Syria, one that pitted jihadi against jihadi, al Qaeda against the upstart group that calls itself Islamic State run by the self-proclaimed “caliph” known as Abu Bakr al Baghdadi.

One week ago, all that seemed to be turned on its head during the bloody terror attacks around Paris. Two men who slaughtered journalists at the satirical weekly Charlie Hebdo claimed they owed their allegiance, and were assigned their mission, by the most militant heirs of Osama bin Laden: the Yemen-based leaders of al Qaeda in the Arabian Peninsula (AQAP). But a third killer, who murdered a policewoman and then four Jewish shoppers in a kosher grocery, and who claimed he “synchronized” his attacks with the others after helping them fund their operations, announced he owed his allegiance to Islamic State, widely known as ISIS.

Do the Paris attacks signal some sort of rapprochement or coordination between the two bitterly opposed branches of the same jihadi lineage? Could they augur a new wave of attacks throughout Europe or, indeed, the West?

On Thursday night, a series of counterterror raids in Belgium targeting fighters returning to Europe from Syria seemed a further confirmation of the risks ahead. Two suspects were killed and one wounded in a shootout in the normally placid little Belgian town of Verviers.

Intelligence analysts in the Middle East, Europe, and the United States are searching for answers in the various communiqués issued since the Paris attacks, including an 11-minute video from AQAP released Wednesday that claimed responsibility for the murder of the cartoonists as revenge for their caricatures of Muhammad. But the delphic declarations of the Paris murderers themselves, who had worked together long before ISIS existed, probably are not clear indicators of a broader reconciliation among al Qaeda and ISIS.

What’s much more important is what’s happening on the ground in Syria, and there, to borrow a phrase or two from the business pages, the attempt by ISIS to stage a hostile takeover of the global jihad movement and squeeze out al Qaeda seems to have slowed. And while it may be far too early to talk about a merger, the two groups have begun talking.

So, the AQAP video claiming credit for the Charlie Hebdo attack is studiously diplomatic. It embraces the slaughter carried out by the brothers Chérif and Saïd Kouachi, but distances itself from the murders committed at the kosher grocery by ISIS-affiliated Amédy Coulibaly. These were a “coincidence,” says the AQAP leader in the video, who nonetheless calls Coulibaly a “brother.”

A Syria-based Salafi cleric with links to both ISIS and al Qaeda tells The Daily Beast that this moderate, fraternal language is significant. He points out that only a few weeks ago al Qaeda luminaries were calling anyone associated with ISIS khawarij, meaning deviant Muslims serving an anti-Islamic agenda.

For most of 2014, fighters from al Qaeda’s affiliate in Syria, Jabhat al-Nusra, joined moderate and Islamist Syrian rebels in battling ISIS. Al Qaeda-aligned theologians denounced al Baghdadi’s theological presumption in declaring himself the “caliph” and demanding fealty from all Muslims everywhere.

ISIS relentlessly sought to cajole affiliates like AQAP to break from al Qaeda and coaxed non-aligned jihadis to swear allegiance to al Baghdadi. The most significant to date to align with ISIS being the largest Egyptian jihad group, Ansar Beit Al-Maqdis (Champions of Jerusalem), which renamed itself the caliphate’s Sinai Province.

Even today, some analysts interpret the AQAP video claiming credit for the attack on Charlie Hebdo as an example of continuing jihadi rivalry rather than as evidence of softening competition between the archrivals.

According to intelligence analyst Bruce Riedel of the Washington-based think tank Brookings Institution, “the most interesting part of the video is the prominence it gives to al Qaeda’s emir, Ayman al Zawahiri, whose orders it says led to the ‘implementation’ of the blessed Battle of Paris.” Riedel notes that by singling out Zawahiri’s leadership, AQAP “implicitly snubs Abu Bakr al Baghdadi’s claims to be the caliph of the global jihad.”

But in recent weeks there have been signs of a mood shift between the rival jihadis amid efforts to broker a rapprochement championed by some al Qaeda veterans linked to AQAP. And there has been evidence of increasing operational collaboration in Syria with recruiters and people smugglers working for both groups at the same time. Al Nusra and ISIS-aligned fighters have cooperated in the Qualamoun, the mountainous region along the Lebanese-Syrian border, where both groups have been battling Hezbollah, the radical Lebanese Shia movement supporting the government of President Bashar al-Assad.

Last November, the Khorasan network of al Qaeda veterans in northern Syria—they were targeted in two waves of U.S. airstrikes last autumn—brokered a meeting between al Nusra leaders and ISIS, according to senior members of other rebel factions. Al Nusra’s overall commander, Abu Mohammad al-Julani, attended the meeting.

According to the rebel sources, Khorasan was an outlier on the rapprochement front, seeing a role for itself in securing an end to the internal conflict between the archrivals. The Khorasan veterans have close ties to AQAP’s overall leader, Nasser al-Wuhayshi, an authoritative figure across al Qaeda, who was appointed by Zawahiri in 2013 as his deputy and is considered his likely successor.

Results became evident on the ground in northern Syria soon after the November meeting as a detachment of ISIS fighters joined al Nusra in an offensive on two rebel militias favored by Washington.

Since then, ISIS fighters have avoided interfering with al Nusra’s self-declared emirate in Idlib. And, noticeably, the al Qaeda affiliate has adopted harsher governance tactics in territory it controls in northern Syria, including more beheadings that mirror the barbarity ISIS employs. One Islamist rebel, Muhammad al-Amin, complained in a Facebook statement recently that “moderates” in al Nusra had been sidelined as the group’s leadership focused on prioritizing an ISIS-like emirate and appeared intent on imitating al-Baghdadi.

This convergence in governing style may have helped the Khorasan veterans pull off last November’s meeting between rivals.

Current and former U.S. officials who are trying to piece together a full picture of the Paris terror attacks remain highly skeptical that archrivals ISIS and al Qaeda can bury the hatchet completely and develop serious collaboration—and they say they are sure a merger can’t take place for as long as al Baghdadi insists he is a caliph and thus the boss of all Muslims.

But a Mideast-based French intelligence official says accepting the AQAP claims that it was just “coincidence” that the Kouachi and Coulibaly attacks took place at the same time “stretches credulity.”

“The Kouachis and Coulibaly were recruited by the same 19th arrondissement cell and are part of the same terror network; Coulibaly’s wife and Chérif’s wife called each other 500 times and those conversations are likely to have included their husbands—and at no time do they jointly plan or even mention to each other what they are going to do?” That is unbelievable.

Aside from the meeting AQAP elements brokered last November in northern Syria, the leaders of the al Qaeda affiliate in Yemen have been careful to offer the prospect of jihadi unity while rebuking publicly al Baghdadi for claiming leadership of the global jihadi movement. One of AQAP’s top clerics, Harith bin Ghazi al-Nadhari, mixed condemnation and conciliation in a video posted by the group last year. He criticized ISIS for claiming Yemen for its caliphate while denouncing the U.S.-led airstrikes on the Islamic State, saying, “Their blood is our blood, and their wounds are in our hearts, and supporting them is a duty upon us.”

Whatever their role in the Paris slaughter, the two most fearsome terrorist organizations in the world are trying to find common interests and pursue a common cause: the fight against the West.