This story was written by Lexi Belculfine based on her reporting and that of Liz Navratil, Moriah Balingit, Jonathan D. Silver, John Allison, Annie Siebert and Andrew McGill of the Pittsburgh Post-Gazette.
Their faces showed the trademark fatigue of marathon finishers.
But as Andy Howard, a native of Moon, watched them stumble into the Boston hotel, he noticed something different: They appeared frightened and dumbstruck, the euphoria that comes from completing a marathon erased from their faces.
After Mr. Howard, 24, and his sister, Samantha McNally, 26, finished the Boston Marathon on Monday, they retreated to the Sheraton Hotel about a block from the Copley Square finish line, where two explosions killed three people and injured at least 100 others around 2:50 p.m.
Outside the hotel, he said, were signs of the chaos: the scream of sirens, the crush of police and emergency personnel. In a park nearby, everyone crowded around, cell phones and tablets in hand, anxious for updates.
The Boston Marathon is an institution for runners and for the city that hosts it, a race that's distinguished by the enthusiasm and volume of spectators, said Mr. Howard, a law student at the College of William & Mary in Virginia.
Much of Boston takes the day off because it coincides with Patriot's Day. And Mr. Howard said nearly every mile of the course was packed, sometimes three to four people deep.
Dozens of Pittsburghers -- runners and spectators -- were in Boston for the race. According to a registry of runners, 51 people with Pittsburgh addresses had registered to run.
Swisshelm Park resident Claudia Davidson, 60, crossed the finish line at 2:45 p.m. Drained from the race, she hadn't even gotten her medal when the first blast resounded.
After watching video of the explosion on the news, Ms. Davidson, an attorney who works Downtown, realized she had been running for a time alongside one of the race participants who could be seen falling down.
"Boston is the premier marathon in the world. People come from all over. Many people strive and struggle very hard to get here," she said. "And this is just awful. Just awful."
Veteran runner Michael McParlane, 61, of Park Place registered for the Boston race but several weeks ago decided not to run because of a nagging calf injury.
His race times range from 3:53 to about 4:06, though he said he would have taken Monday's run slower than usual because Pittsburgh's 26.2-mile race is in three weeks.
"You have to wonder if fate intervenes in these kinds of things," Mr. McParlane said. "... This is more than a coincidence, I'm sure."
If his injury allows, Mr. McParlane said he'll run in Pittsburgh, but the tragedy in Boston made him consider the future of marathons.
"I'm hoping that the community stays together, [organizers proceed] and that charities continue to earn funds," he said. "It's just devastating that [anyone] would think to attack a race."
KDKA-TV reporter Andy Sheehan said he was in the last wave of runners to complete the Boston race on Monday, finishing in just under four hours. That put him about 200 or 300 yards past the finish line when the first bomb went off, he said.
A "horrific percussive explosion ... shook all the buildings," Mr. Sheehan said. "I turned around and saw this towering cloud of smoke hovering from the finish line area. Sort of immediately you have one thought, and that's that this would have been a terrorist thing."
The second explosion came quickly after the first, he said, and marathon workers told people to remain calm and continue moving.
"It's a shame. It's the Boston Marathon. It's a holiday in Boston," he said. "I was just thinking along the race course what a great celebration of American freedom it is. To have this happen is awful."
Selena Schmidt, a former Pittsburgh City Council staff member who also worked with Western Pennsylvania nonprofits, attended the race to support a friend. Ms. Schmidt now works in Cambridge, Mass.
"This was my first marathon, so I wasn't sure if it was some local tradition -- a cannon going off, or something like that," she said. "But when the second blast went off not even a minute later ... people just began to pour out."
The thermal blankets that runners get as they arrive at the finish line weren't available, she said.
"I saw so many people talking off their shirts and jackets to drape over the runners," she said, adding that she saw others try to help in a different way.
"A group of people gathered to pray for the public safety workers," she said. "... The public safety workers are excellent -- the police, the fire, the ambulances -- very well organized, getting people out the area."
Jon Kissel, part of the Steel City Road Runners running club in Pittsburgh, spent the hours after the bomb blasts making sure his fellow marathoners were OK. All were unscathed.
"Gradually, one by one, we were managing to all connect with one another. It's the beauty of the social media age, I guess," said Mr. Kissel, 29, of Spring Hill, who was running in his second Boston Marathon. He was at least a half-mile away from the explosion and did not hear it.
Mr. Kissel, who is the community and member relations coordinator for the Pittsburgh Marathon, described mixed emotions -- the anticipation of the runners, the terror of the bombs and the coming together of the community in Boston.
Marathoners "all woke up this morning for the greatest event in our sport," he said. "Yet it baffles me there were a few people who woke up with very different intentions. It's spooky."
After he crossed the finish line, Mr. Kissel said strangers would see his medal and congratulate him. "Now at the airport, it's a very somber, polite nod, like 'good job today, but what a day...' "
Mr. Kissel said he plans to be back in Boston next year, undeterred by Monday's horror.
"I will be back every year that I can qualify for it," he said. "We distance runners, we don't stop. We keep going. Our sport's all about perseverance. This sort of thing only instills more solidarity among us to kind of bind together and continue doing what we do."
The Associated Press contributed. First Published April 15, 2013 8:30 PM