>> so it may be that they got training and then you know went into operation after just a few months. there seems to be some significant planning here. there was a lookout at the museum who alerted the gunmen when these buses were going to arrive so they could start attacking the buses that morning. so some organization here. this suggests a more kind of sophisticated attack perhaps linked to a more established terrorist outfit. isis isn't the only candidate here. there's also sharir in tunisia. they have 40,000 followers in the country. there's a north african al qaeda affiliate which has a presence in the mountainous region near the algerian border which has been the most active terror group. al qaeda in north africa also have a presence in libya. not impossible that they could have trained with another group, not isis, in libya. the investigations i think will uncover more as we move forward. >> let's talk about yemen now.