Investigators seem to be focusing on three critical hours near the finish line. One hour before elite runners camesweeping up Boylston Street, they did one final security sweep, checking for the bombs there. Then 17,500 runners so came up crossed the finish line and other6,000 were on the way when the first bomb went off about three hours after that security sweep. 12 seconds after that the second bomb went off, some distancedown the road.

 

So what are investigators looking for, let me rotate this around so you could look right down the race cross here. They are looking for anybody who saw something in this area that would directlyre late to the dropping of the package. Somebody doing something suspicious that would really jump out. That's why they are asking for all those photographs. All that video to see if that might find clues to things like this: this photographs have attracted a lot of attention, because you see that package sitting right here? That's right near the spot where one of explosions was. A lot of people wondering if that was one parcels that may have been dropped off here blew up. So investigators are going to try to find people who can say yes,I saw someone with the package like that. Yes, I saw this person leave it there that's sort of thing. It's a trick job to get done. But they have something that might help them out that's really unique to a race circumstance like this.Every single runner on this course had to wear electronic tracking tag. That'show race officials keep tracking who is coming down the course. Now the runners may not be able to tell them anything because they are focusing on running. Butthe runners could know where families and friends have gathered alongside to watch their progress. So if investigators say look we have witness here whosays they saw a man or something. We have went down here who says they saw thatthey think is the same man. This would allow investigators to go through therunners, through the race organizations and say where were your families andfriends? Were they in the middle here ? Did they see this person pass bysomething they may not think much of it. Now, may really matter, normallyinvestigators would have to wait for those people to come forward. In thiscase, they have a way to reach out to them and could prove very important.

 

This is a quote from the late children's TVstar Mr. Rogers that we mentioned in yesterday show talks about in times ofdisaster looking for the helpers. There are plenty of those in Boston on Monday. After the bombs went off, first responder ran toward the site of theblast. Police, paramedics, other emergency personnel and other people ordinary citizens also jumped into the help. One of them was Carlos Arredondo. He was inthe Marathon to honor his two sons. One of whom died when serving in Iraq. Arredondo said he's a member of the Red Cross and has some emergency training.He came to the aid of a man with severed leg wounds and stayed with him until paramedics arrived.

 

Dr. Natalie Stavas, a pediatrician was running the marathon with her dad. They were almost at the finish line, whenthe explosions happened. Anderson Cooper asked her about what she saw she made her way over to help.

 

You are a doctor. You are obviously trained to see blood to see casualties in dead.

 

It was horrific. It was the worst thing that I have ever seen.

 

Doctor Stavas moved to the crowd giving medical aid to several victims of the bombing. Other people found ways to helpaway from the blast side. Andruzzi, a former player with the New EnglandPatriots, saw an injured woman being carried by what look like a teenager. Heran to help carrying the wounded women to safety. Another runner finished the race ten minutes before the bombs went off. She offered her cell phone to astranger who was trying to find her husband.