Rescue personnel aid injured people near the finish line of the 2013 Boston… (Stuart Cahill / Associated…)
When the two explosions hit the finish line of the Boston Marathon, some onlookers ran toward the blasts -- to help.
Confusion whirled around Boston after the explosions, which left at least two dead and more than 20 injured Monday, a day that had been devoted to one of the nation's most famous races. Instead, blood streaked the sidewalk near the finish line, and runners, friends and family struggled to find one another as police raced to the scene.
Hayden Cardy, 18, of San Antonio, and his sister had just watched their mother cross the finish line a minute before seeing the explosions, and he was wrenched with fear.
“That was absolutely scary: having no idea where she was, what would happen next," Cardy told the Los Angeles Times. “It was busy, and it was scary, and I’m just happy that my mom made it out."
PHOTOS: Explosions at Boston Marathon
The conspicuous location of the blasts and the celebrated nature of the event raised the specter of a terrorist attack -- but that kind of speculation could not be confirmed so early after the tragedy, and Boston, and its guests, were left coping with the chaos.
“Given for someone to do this in front of Boston, on the national stage, it’s really tragic," Kate Plourd, 28, of Boston, told The Times. She had finished running 20 minutes before the blasts hit and was being treated in a medical tent for post-race illness when she heard the first explosion. Officials soon cleared the tent.
"I got very emotional because many of my friends were behind me in the race," said Plourd, who didn't have her phone and was disconnected from her friends for a while, not knowing whether they were safe.
"There are a lot of runners walking around without blankets," Chi-Ting Huang, 43, of Belmont, Mass., told The Times; she saw the aftermath of the blasts -- the smoke and the papers drifting up in the air -- while watching the race from the third story of a building down the street. "It's pretty cold out if you haven't been running. ... There are also a lot of very worried runners out there looking for friends."
, 43, a Boston food writer, told The Times he was at a marathon party one door down from where the blast happened.
VIDEO: Boston marathon explosion
"[The] explosion rocked my ear drums," said Helterman, who also got debris in his eyes. He and 20 other marathon partiers huddled in the back of the building, trying to decide what to do, and "frantically" calling loved ones, he said.
"Finally, we decided to exit via fire escape," he said. He popped out a window screen and made his way out.
As with any public event, much of the horror, clamor and confusion was documented over social media, which, when taken together, constituted the first draft of what happened in Boston on Monday, recreated below.
Warning: Many of the following tweets describe graphic accounts of the tragedy.