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French National Police/AFP/Getty Images
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(CNN) —  

Western intelligence officials are scrambling to learn more about possible travel of the two Paris terror attack suspects, brothers Said and Cherif Kouachi, with new information suggesting one of the brothers recently spent time in Yemen associating with al Qaeda in that country, U.S. officials briefed on the matter told CNN. Additional information from a French source close to the French security services puts one of the brothers in Syria.

If correct, the travel leads to a mosaic of potential influences that investigators will need to sort through as they seek answers to whether the attack is connected to any specific terror group or whether they were merely influenced to act in the name of a group.

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A U.S. official says the United States was given information from the French intelligence agency that Said Kouachi traveled to Yemen as late as 2011 on behalf of the al Qaeda affiliate there. Once in Yemen, the older brother of the two received a variety of weapons training from al Qaeda in the Arabian Peninsula (AQAP) – the affiliate in Yemen – the official said, including on how to fire weapons. It is also possible Said was trained in bomb making, a common jihadist training in Yemen. Two other U.S. officials confirmed that information about the Yemeni travel was passed to the U.S. from French intelligence agencies.

In addition, French Justice Minister Christiane Taubira told CNN’s Christiane Amanpour in an interview broadcast on CNN International that one of the brothers traveled to Yemen in 2005. Taubira would not say which brother.

All the U.S. officials strongly emphasized the U.S. assessments are preliminary and a great deal of information about the suspect’s travel still needs to be confirmed.

There is also scrutiny of travel by one of the brothers to Syria. A French source close to the French security services tells CNN’s Nick Paton Walsh that investigators have evidence to suggest one of the brothers – it is unclear which – traveled to Syria sometime in the past year. The French source added that the French are working on a hypothesis, according to the officials he has spoken to, that this brother could be affiliated to ISIS.

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In addition, the younger brother Cherif Kouachi, attempted at one point to join jihadist waging war in Iraq against the U.S. and the coalition.

It is not yet clear to the U.S. whether Said Kouachi ever met Anwar Al-Awlaki, the AQAP chief of external operations in Yemen. Al-Awlaki was killed in a U.S. drone attack in 2011.

Both officials emphasized there is still a great deal to be determined about the suspect’s travel to Yemen, but that the Yemeni visit is emerging as a key element of the preliminary U.S. assessment the Paris attack was related to the brothers’ loyalty to the AQAP agenda and its magazine “Inspire,” which last year called for the death of the Charlie Hebdo editorial director. The first official noted given the substantial time lag between the Yemen travel and the Paris attack, there may be no easy way to characterize whether the Paris attack was ordered specifically by AQAP or the brothers were simply inspired by the group.

In an interview with CNN’s Amanpour, French Justice Minister Taubira refused to say whether the brothers were associated with the terror group al Qaeda in Yemen.

“We have to be sure that it’s very important to be sure before talking because we don’t want to panic people, it’s very important for us to ensure security for all French people but at the same time we have to be very serious very firm very sure of everything we say so all these elements are part of what a judge prosecutor and policeman use in order to reach the truth and people can talk about this but for us, the government and also the judges, we have to be very careful and be sure before talking,” Taubira said.

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But U.S. intelligence is also exploring an alternate possibility, the U.S. sources said, that the attack was either directed by AQAP or influenced by propaganda, specifically Inspire magazine, and other al Qaeda social media messaging.

One U.S. official says this attack appears to be a strong potential example of the blended counterterrorism threat that is growing with perpetrators having multiple loyalties and ties, but perhaps no direct face to face connection with some of the groups they claim to follow.

A U.S. official tells CNN the “big worry” now is that with the AQAP-connection there could potentially be other so-called foreign fighters out there who also traveled to Yemen a number of years ago and then are laying low somewhere. U.S. and foreign intelligence agencies are scrubbing through all their intel, but the plain fact is right now, they just don’t know.

The U.S. foreign fighter issue in Yemen is just as concerning as the foreign fighter issue in Syria, U.S. officials tell CNN. When asked whether there’s been uptick of Americans going to Yemen, one U.S. official said, “Well, there definitely hasn’t been a downtick.”

CNN’s Pamela Brown and Nick Paton Walsh contributed to this report