The killing of the suspected ringleader of the Paris attacks, Abdelhamid Abaaoud, helps avenge the 129 people who died and the hundreds injured that he and his cohorts were responsible for in last week's horrific assault. The death of Abaaoud, implicated in four out of six attacks foiled in France since just this spring, also prevented any more damage he might have been plotting. Ideally, though, it would have been far better to have caught Abaaoud alive for he would have been a goldmine of information on how Daesh (the self-proclaimed IS) operates, where its positions are in Syria, where its cells are in Europe and elsewhere, and what other attacks it had in the pipeline. It also would be foolish to believe that Daesh has been tamed or will not strike again simply because one of its operatives is no more. There are probably hundreds, maybe even thousands, of Abaaouds out there bent on killing anybody and everybody who does not agree with their perverted and violent logic. Abaaoud's movements raise serious questions about security in Europe. He was high on French and Belgian wanted lists and yet managed to travel from Syria to the heart of Paris without ever leaving a trace. Belgian authorities knew he'd gone to Syria, but didn't realize he'd returned to Europe. Why? If France only learned as much after last Friday's carnage and only after receiving information from Morocco's intelligence agency, then there is something gravely amiss in Europe's security coordination and cooperation. In fact, Abaaoud had bragged in the past of being able to move between Syria and Europe at will. Bolstering European borders obviously has not been implemented fast enough and does not go far enough. The flood of refugees into Europe in the summer, and to a lesser extent in the US, has also made the possibility of members of Daesh among them extremely likely. The coalition going after Daesh in Syria, although now including the three strongest militaries in the world - the US, Russia and France - must also widen. It was always a big question whether Daesh would stay put in Syria and Iraq and not export its terror farther. Aside from clashes with Egypt's army in Sinai, it had appeared that the group was not spreading its wings elsewhere. But all that changed after Paris. It is moving its way across the borders of the Middle East, expanding beyond Syria and Iraq, now into Libya, Egypt and Afghanistan and in recent weeks has launched attacks into the Sinai, Beirut and, as we saw last Friday, into the heart of Europe. Abaaoud's death does not mean investigators' work is over. Far from it. For one, at least one Paris terror suspect, Salah Abdeslam, is still at large. And the threat from Daesh, which boasted about the attacks and threatened more worldwide, remains very real. Daesh looks increasingly like it will use European recruits to carry out attacks back home, particularly in France. With every day that passes, the danger of a Daesh-inspired or Daesh-sponsored attack grows. Innocent lives are still at risk. They will probably be at risk for many years. Killing the leaders of Daesh is not enough. Fighting them in Syria is not enough. All of a sudden, Syria does not seem so far from Paris. The killings showed how easily and quickly violent ideas are now able to cross borders.