secretary of state rex tillerson is in the uk today trying to calm the nerves of this very important ally by taking responsibility for investigation leaks to the media. meanwhile, new arrests in the raids in manchester today. eight people now in custody and, according to reports, a suicide bomber, salman abedi, had just called his brother over in libya 15 minutes before the attack in that concert. let's bring in cnn investigative reporter michael weiss, the co-author of "isis: inside the army of terror." welcome back. >> thank you. >> the fact that he picked up the phone and called his brother from that manchester arena in libya, what does that tell you? >> oftentimes the jihadi networks are populated by members of the same family. the reason being, it's simply easier and you're more likely to