When Anne Trumbore finished the Boston Marathon, she, like many of the other runners there, was in a post-run daze. The blasts came as she stood in line, wrapped in a heat blanket to try to stay warm, to get her personal effects from a bus.
"There was this loud bang, the buses shook, and everyone turned around," she said. "People were still suffering the after-effects of the run, and we only saw what looked like white smoke. Everyone thought it was some sort of celebration -- like maybe a cannon."
The twin explosions that killed three and injured hundreds more came at around 2:45 p.m. near the finish line of the race.
At Tuesday press conference, Richard DesLauriers, FBI special agent in charge of the investigation, said that the explosions came from bombs -- possibly pressure cookers stuffed with explosives and what appeared to be BBs and nails -- that were placed in black nylon bags. DesLauriers said that so far nobody has claimed responsibility and that "the range of suspects and motives is wide-open."
Trumbore, a Palo Alto resident, said it didn't occur to her or the other runners that something was wrong, partly because of the daze they were in and partly because many of the nearby volunteers didn't appear visibly alarmed. She heard sirens approaching the area but initially dismissed them because they aren't a particularly rare occurrence at the finish line of a marathon.
"You often hear sirens -- at the end of a marathon people go to the hospital, get hurt or have heart attacks -- but your brain doesn't immediately go to a bombing," she said.
It wasn't until 10 or 15 minutes after the blasts that she realized that something was wrong. All the race volunteers began running toward the finish line, and the sirens grew more intense as she started hearing people mention the dead and injured in the cell-phone conversations of passers-by.
Dr. George Velmahos of Massachusetts General Hospital in Boston said in a press conference Tuesday morning that several of the victims admitted to the trauma ward received amputations "because of the devastating effects of the bombs."
"Many have severe wounds, mostly in lower parts of the body, related to blast effects of bomb, as well as small fragments that entered the body: pellets, fragments, nails," he said.
Palo Alto resident Riya Suising said she was waiting in line at the marathon's complimentary massage booth about 45 minutes after completing the race when she heard the explosions.
"It sounded like thunder, but it was different," she said. "The staff told all the runners and massage therapists to evacuate. Then we knew it was serious."
Suising, who was three blocks away from the blasts, said she began hearing signs of the explosions, including sirens and passers-by.
"I saw two ladies holding each other, crying, in tears, maybe about a relative," she said. "It turned out not to be a great day, but we're all very fortunate to be safe."
DesLauriers said the investigation "is in its infancy," but more than 1,000 law-enforcement officers from several agencies are chasing the more than 2,000 leads that have been received.
Palo Alto resident Jessica Williamsen confirmed Monday that she had finished about 30 minutes before the blasts occurred and that she and her family were well clear of the area.
Palo Alto resident Felice Kelly went to support her sister, Natalie, at the race. She followed her sister through a late portion of the race until the crowds were too thick for her to continue.
After Natalie finished the race at around 2 p.m., the two sisters were getting a sandwich about three blocks away when someone ran in, saying that shots had gone off. Neither of the sisters, nor Menlo Park resident Laura Blaich, heard the blasts. Blaich was also about three blocks away at a public transportation station.
Kelly said she worries about the effect the blasts will have on the sport.
"In a weird way I hope it doesn't change marathons, partly because they're public and open and free -- there's a bit of risk you have to accept."