greece, going by boat to syria, all of that is possible, and there s very little control over those board eers. reporter: it would be an alarming escape. his la the chairman of the house homeland security committee says authorities are getting closer. i think they re closing in on him. that s good news. there are many involved in this plot. it s very sophisticated, an external operation we ve seen from isis. reporter: investigators are piecing together the movements before the attacks. french place say they bought ten detonators and batteries. the store manager alerting authorities after the arrest warrant. the trail has gone cold, and they re looking for any kind of clue, people he met.
french investigators looking to the possibility he escaped to syria sources tell cnn. if he made it over land from france to turkey, it would have been very easy for him to get into syria, same, he could have also done that via greece by boat to syria. all of that is possible and there is very little control over the borders. reporter: still, it would be an alarming escape by europe s most wanted man. his last known whereabouts were belgium. authorities are getting closer. i do think they are closing in on him and that s the good news. there are many involved with this plot as very sophisticated plot and external operation and we see from isis. reporter: investigators are piecing together the november 13th attacks. french police say salah abdeslam