president. that nation, though, still in shock over the killing, the brazen killing of a police officer thursday in paris. an attacker who apparently support isis. >> we've now learned the gunman had been under investigation by french counterterrorism officials for the past several weeks. cnn's melissa bell joins us from paris with the latest. i know you've been covering the election there, melissa, for some time. now we have the shadow of this terror attack. >> reporter: the shadow of this terror attack, of course, over a campaign over a political landscape, natalie, that involves essentially all of the 11 candidates, four that are leading the polls, with all of them around the 20% mark. it is extremely tight. then you have also this very large group, historically high numbers of french voters, who have jet yet to make up their m. there is everything to play for. the sense is that it wouldn't