Terror at Boston Marathon: 3 dead, 144 wounded

It was a gruesome end to what should have been a celebration of triumph. One man's legs were instantly blown off, yet he kept trying to stand up. Exhausted marathoners had to muscle the energy to flee the bloody scene. And more than 140 people remain hospitalized, some in critical condition. As authorities try to figure out who triggered the deadly bombings Monday at the Boston Marathon, which killed an 8-year-old boy and two others, many are at a loss to explain why anyone would target the annual event that celebrates thousands of runners from around the world.Both blasts happened in quick succession, near the row of international flags that led up to the finish line. The impact was so powerful, it whipped the limp flags straight out as if they were caught in a hurricane. It also knocked 78-year-old runner Bill Iffrig to the ground."I was just approaching the last straightaway to the finish line, and I had a good day and was feeling really good, and I got down to within about 15 feet of the finishing apron and just tremendous explosion, sounded like a bomb went off right next to me," Iffrig said. "The shock waves just hit my whole body and my legs just started jittering around. I knew I was going down," he said. Iffrig was not seriously injured. But trails of blood, severed arms and legs and other body parts littered the scene nearby. At least 144 people were hospitalized, with at least 17 in critical condition and 25 in serious condition, officials said. At least eight of the patients are children. A terrorism expert briefed on the investigation said doctors are "pulling ball bearings out of people in the emergency room," suggesting the bombs were designed to propel shrapnel. But Dr. Ron Walls of Brigham and Women's Hospital, which received 31 patients, said the debris found in some patients' wounds did not appear to be from ball bearings. "Everything we saw was sort of ordinary ambient material that could have been propelled by the blast but was not added to the device," Walls said. "It was not the kind of things that would be added to a device to make it more injurious than it otherwise would be."At Massachusetts General Hospital, several patients suffered from injuries to lower limbs that will require "serial operations" in the coming days, trauma surgeon Peter Fagenholz said Monday night. He said the most serious wounds "have been combined, complex lower injuries that involve blood vessels, bone and tissue." Numerous patients had to have limbs amputated, Fagenholz said. "Just like" going back to Iraq Nurses Stephen Segatore and Jim Asaiante were stationed near the finish line, expecting to treat the usual ailments from runners -- cramps and dehydration. Suddenly, they found themselves in a battlefield, with blood and debris everywhere. "For me, it was just like going back to being in Iraq in 2006-2007," said Asaiante, an Army captain who served an 18-month tour. "I heard the first IED, and I know there's never one. The bad guys always set up two or three" improvised explosive devices, he said.

From celebration to carnage

The plumes of smoke and images of bloodied victims running down streets also triggered haunting memories of the terrorist attacks of 9/11. Tami Hughes had just crossed the finish line and was looking for her husband when she heard a deafening explosion. "I didn't know if it was a small aircraft going into the building," Hughes said. "I turned around and immediately saw the whitish-brownish smoke billowing up four or five stories and I couldn't believe that, you know, could it be a bomb? "And I stared at it and about five or seven seconds later, when the second one went off, I knew immediately that it was something coordinated or organized, because I had been ... down in the financial center, 9/11. So you immediately go back to those moments where OK, where is the third one going to be?" The hunt for clues Investigators don't know who was behind the attack, or whether it was spawned domestically or from afar. But federal authorities are classifying it as an act of terrorism. A federal law enforcement official said both bombs were small, and initial tests showed no C-4 or other high-grade explosive material, suggesting that the packages used in the attack were crude explosive devices. The explosions went off near the finish line at about 4 hours and 9 minutes into the race, within a 10-minute window of the average finish time for the marathon. But the fact that the blasts took place near the end of the race "seems to indicate this was not geared toward maximum damage," said a former federal law enforcement official who now works in the intelligence community. "It may speak volumes about the (level of) planning that went into this," the source said. "It raises questions ... why didn't the bombs go off when the crowd was packed in like sardines when the winners were crossing the finish line? It could mean the people behind it couldn't get access to the area when they originally intended." Officials have no suspect in custody, but many people are being questioned, Boston Police Commissioner Ed Davis said. Investigators warned police to be on the lookout for a "darker-skinned or black male" with a possible foreign accent in connection with the attack, according to a law enforcement advisory obtained by CNN. The man was seen with a black backpack and sweatshirt and was trying to get into a restricted area about five minutes before the first explosion, the lookout notice states. Davis said authorities found at least one other explosive device that they were dismantling. But Rep. Bill Keating, D-Massachusetts, said two undetonated devices were found. One was discovered at a hotel on Boylston Street near the bomb site, and another was found at an undisclosed location, said Keating, a member of the House Homeland Security Committee. He called the bombing a "sophisticated, coordinated, planned attack." The unexploded devices could provide a treasure trove of information such as fingerprints and indications of the bomb maker's design, said the former federal law enforcement official. Late Monday night, authorities said they were still getting reports about suspicious packages, but some may be abandoned belongings left by fleeing spectators. Davis said while no new devices had been found so far, he is "not prepared to say we're at ease at this point in time."