The explosions came one after another at the finish line of the Boston Marathon, followed by the screams of the injured and the chaos of thousands of people fleeing.
“We heard a huge boom, and the building was shaking. Then people started screaming,” said Maya Hauer, 23, who was on the third floor of a building about two doors down from where the first bomb exploded on Boylston Street, enjoying a party in honor of the marathon on a cloudless spring day.
After the second bomb went off farther down Boylston, Hauer looked out the window and saw, in the street, a lone leg that had been amputated by the blast.
“There was blood all over Boylston. And shattered glass everywhere,” Hauer said. Hauer joined thousands of people who were fleeing.
PHOTOS: Explosions at Boston Marathon
“It was chaotic,” said spectator Jeffrey Rothschild. “People were scared and crying.” Rothschild, who was about 350 yards away from the finish line, said that after the first explosion there was silence. After the second, many began to flee. His companion smelled sulfur.
Some of the Bostonians and tourists who were watching the race inadvertently captured the explosions on their cellphones and cameras. One eyewitness who posted his video on Vine — using the name of “Doug” — had been filming the sparse crowd of runners who were within steps of the blue and yellow finish line as a burst of red flames and white smoke shot into the air behind a line of flags that were lining the route.
The video showed volunteers in yellow jackets, who had been clapping at the edge of the route, crouching over and running for cover as the explosion occurred behind them; one of the marathon runners in a salmon-colored T-shirt fell to the ground on the marathon route.
Jackie Bruno, a reporter with New England Cable News at the scene, reported via Twitter that she and her cameraman were shaken by the force of the explosion: “I saw people’s legs blown off. Horrific. Two explosions. Runners were coming in and saw unspeakable horror.”
Samantha Bissonnette, 22, a senior at Tufts University, was about half a mile away from the finish line when she heard the explosions, one after another.
VIDEO: Boston marathon explosion
“The runners seemed confused and slowly panic started to set in,” she said via text message. Bissonnette found herself standing next to a woman and her girl who was crying because she could not find her father, who was running in the race. Finally, they found her father, who picked up his daughter and began to weep with her.
Many runners and spectators, including Bissonnette, reported that their cellphones went down.
Eric Giandelone had finished running and was drinking a celebratory cup of coffee and watching other runners cross the finish line when he heard a loud blast.
“"I looked up and I saw debris flying," said Giandelone, 34, of Chicago, who estimated that he was about 150 yards from the first blast and 50 from the second.
Runners and spectators were running from the finish line when the second explosion went off, this one a little farther from the finish line where everyone had been heading, he said.
“There were people who were missing limbs, yes,” Giandelone said. “I saw more people who were hurt from the second explosion because I had to run by that area.”
Alex Garcia, the assistant manager of Casa Romero, a restaurant near the finish line, was getting ready for a busy day at the restaurant when staff heard the explosions rip through the finish line. He ran outside and saw “everyone was running, and people were crying, bystanders who were there to support and cheer for the people.”
“I am frightened,” he said. “I don’t know if another one is going to go off. The police is telling everone to leave, all the restaurants. ... We’re in shock.”
Ellen Jean Hirst of the Chicago Tribune also contributed to this report.