alert, a new lead in the investigation into the nairobi mall massacre leads police all the way to scanned neva. scandinavia. jenna: a training twist to the strange twist to this story. new evidence about a possible suspect, trying to figure out if he s one of the gunmen released in this video of the terror attack. the horrifying surveillance footage shows the chaos and carnage as it all unfolds. terrified shoppers running for their lives as four men armed with assault rifles and hand grenades calmly stroll through the complex casually gunning down anyone caught in their path. our senior foreign affairs correspondent greg talcott is live in london with more. what do these new videos tell us about the attack? reporter: yeah, jenna, it is our first long and close look at the attackers and the attack on that kenya shopping mall last month, and it is brutal.