tissue, vascular injuries. they have to be approached oftentimes in kind of a step-wide fashion. >> reporter: and a trauma surgeon at massachusetts general telling nus that press conference that there will be some repeat operations. some injured will have to come back again and again for multiple surgeries. if he has seen anything like this, he said he has never seen this volume, this quantity come into his emergency room, john. >> poppy, as you said, a number of the injured are children. it's tragically no surprised because what you do on marathon monday in boston is go watch the race with your kids, with the entire family and now we do know the identity of the 8-year-old boy who was killed. what have you learned about him? >> reporter: we do.