Some of them could see the finish line a few hundred feet ahead, lined with cheering spectators, a marathoner’s vision of heaven until — after the two explosions, the smoke, the screams and the chaos — it turned to hell. Others were farther back, on Heartbreak Hill, at Kenmore Square or amid the logjam of runners on Commonwealth Avenue who kept piling near the underpass below Massachusetts Avenue, at the 25.6-mile mark — where they should be entering the homestretch but where, around 3 p.m. on April 15, 2013, cops were suddenly barricading the course and telling the stunned, confused runners to turn around.

For them, it is where the 2013 Boston Marathon ended.

The most obvious victims of last year’s Boston Marathon bombings — and the ones most worthy of remembrance and honor — were the three who lost their lives and the 264 who were injured — including more than a dozen who lost limbs — when a pair of homemade explosives detonated near the finish line.

[ Find the complete viewer’s guide to the 2014 Boston Marathon here ]

But there were other, less obvious victims, among them the 5,633 runners still on the course when the race was halted. Of the 36,000 runners in the expected field for Monday’s 2014 Boston Marathon, few will carry motivation quite like those 2013 non-finishers who were invited back by race organizers so they could take care of unfinished business.

Boston first responders recount the aftermath of the marathon bombing and talk about how they, and the city, have moved forward. (Whitney Shefte/The Washington Post)

“People who don’t run say, ‘Oh, you almost finished it.’ But it’s not about the distance. It’s about the race,” said Brian Cotter, a 26-year-old Adams Morgan resident, one of dozens from the Washington metropolitan area asked back to run again this year.

A year ago, Cotter, who works for the Defense Department, was racing in his first Boston Marathon and had just made the turn onto Boylston Street, leaving him about 31 / 2 blocks from the finish line. He heard the first bomb — “Like a dumpster being dropped to the ground,” he said — and saw the second.

“I’m ready to go back,” he said almost a year later, “and finish the right way.”

‘I think the race is over’

Some things most — but not all — Boston Marathon entrants have in common:

They run without a cellphone — a cellphone strapped to a waist or velcroed to an upper arm being a telltale sign of a novice.

They have at least one person and often dozens — friends, family members, neighbors, co-workers — waiting for them at the finish line.

They are capable, generally speaking, of completing a marathon in four hours or less.

Here's where 10 local runners were on the Boston Marathon course when the bombs went off last year.

For many runners who competed in the 2013 race, their individual fates would hinge on how closely those generalities applied to them that day.

“On the morning of the race, I started getting nervous about whether I’d be able to finish it,” said Megan Hoffsis, a 25-year-old Rockville native, “so I decided I’d better bring my phone — in case I had to call my parents and let them know where I was.” That decision helped Hoffsis reunite with her loved ones within minutes of the race being stopped, while other runners required hours.

It was 2:49 p.m. when the bombs went off, about 12 seconds and 210 yards apart from each other at the finish-line area. At the time of the first explosion, the race clock displaying the marathon’s elapsed time read 04:09:43, the top male finishers having finished nearly two hours earlier. For another eight minutes, runners would continue to cross the finish line, now shrouded in smoke, until the enormity of the situation became apparent and the course was shut down.

“I got stopped by a cop right in the middle of Boylston. I could see the finish line. The cop says to me, ‘I think the race is over,’ ” said Cotter, the Adams Morgan resident. “All of a sudden, a guy comes running towards us, covered in blood, his clothes all ripped off. Two officers picked him up and carried him off.”

It would take even longer to stop the runners who were farther back on the course. Some were novices staggering along in their first Bostons, having gained entrance to the exclusive race by raising money for charity. Others were veteran time-qualifiers dealing with injuries, which explains why they still hadn’t finished at a point when most serious runners already had. Many felt a familiar rush of adrenaline as they neared the homestretch.

Melanie Shepherdson, a 42-year-old attorney from the District, was on Commonwealth Avenue, just past Fenway Park, preparing to go through the underpass below Massachusetts Avenue, about 251 / 2 miles into the race, when she and a group of about 15 runners were suddenly halted by police and race officials. The wooden barricades typically used to keep spectators off the course had been lifted and pivoted so they were now blocking the course.

“As the minutes ticked by, the runners started piling up,” Shepherdson said. “Someone said a bomb had exploded, and I suddenly became very emotional. At that moment I felt very vulnerable. I had no reliable information about what was going on. I was scared another bomb could go off. I was exhausted and could barely walk. But most of all I was worried about finding my way to somewhere safe and finding my sister.”

As the logjam of runners grew well into the hundreds, the late-afternoon temperatures began to fall, and the exhausted runners — now struggling to stay warm — stood around unsure of what to do, with no warm clothes and, in most cases, no cellphones.

“Eventually, people started coming out of their apartments, bringing water and trash bags, blankets — anything we could wrap ourselves in,” said Anny Rosenthal, a 64-year-old Bethesda resident who was part of the Commonwealth logjam. “I felt like it wasn’t real. I had just run 25.6 miles. It was taking a long time to process the information.”

The finish line, as most of the runners knew well, was a little more than half a mile away, but none of them would make it there. They had put in all the work, all the sweat, all the miles, and now the reward was yanked away from them.

“That last half-mile is one of the best feelings you can have,” said Lindsey Malm, a 31-year-old Alexandria resident who grew up attending the Boston Marathon with her family every year. “The city, the ambience, the people, the emotions. It’s the best part of the entire marathon.”

“I was so angry the bombers had interrupted my race,” said Gretchen Bolton, a 68-year-old Bethesda resident. “I’m afraid we runners had a very personal reaction after 25 miles. Sentiment for the dead and injured would come later.”

One D.C.-area runner had extra reason to keep going, even after being told the race was over. Bethesda’s Ben Beach, though injured halfway through and reduced to walking, was within about five miles of completing his 46th consecutive Boston Marathon, which would have set an official record. When race officials barricaded the course, Beach, unaware of the depth of the tragedy ahead, took to the sidewalks, joined by a half-dozen friends and family members who had come to celebrate his singular achievement, and headed toward the finish line.

“Eventually we got to about 24.5 miles, just as you’re about to go up the ramp near Fenway Park,” said Beach, 64. “The cops there said, ‘This is the end of the line. You cannot go any further.’ ”

And so Beach gave up his pursuit for his record and set out to find the rest of his family and friends. He was tired, worried and hurting from a calf injury. He was horrified about the reports of deaths and injuries at the finish line. And somewhere deep down, he also began to contemplate what the halted race meant for his streak.

Events kept ‘my family safe’

There must have been thousands who had close calls that day: friends and family members of runners who cycled in and out of the finish-line area, catching a glimpse of their loved one then hustling off to find them around the corner in the family meeting area or deciding on the fly to hold off a little while longer before heading to the finish line — decisions that may have saved them from injury or even death.

For some of the 2013 non-finishers, it was their slower times — as well as the technological advances that make it possible to track the progress of individual runners — that in many cases gave their loved ones extra time to make their way to the finish line.

“My wife, Amy, had just gotten a text update that I was about 45 minutes or so out,” said Russell Smith, a 44-year-old Annapolis resident and a command master chief for the U.S. Navy. “So she left the finish line to get a coffee and was around the corner when the devices went off.”

Hoffsis, the 25-year-old Rockville native, found out later that her parents had moved away from the immediate finish-line area only a few moments before the blasts for one reason: Her mother is only 5 feet 2 and couldn’t see anything there amid the crowds.

“So many events were perfectly lined up that day to keep my family safe,” Hoffsis said. “It was a miracle that I ran with my phone and got one phone call out to my dad, that my leg was hurting and my pace was slowed down [and] that my parents moved position.”

And some, of course, were not so lucky. When Malm, the 31-year-old Alexandria resident, found her family at Cheers — the legendary bar that had been her family’s post-race gathering spot for decades — her mother, Leslie, was “pretty hysterical.” Leslie Malm, it turns out, had been standing about 10 feet from the second explosion and was knocked backward and off her feet by the blast. A man pulled her into a nearby restaurant for safety.

The Malms are a family of runners, with deep roots in New England and the Boston Marathon. The day before Lindsey was born, her father, Robert, ran a 2-hour 34-minute time to finish as the top American male in the race. The 2013 edition was his 34th in a row. Struggling through an ankle injury, he was at mile 18 when the race was stopped.

Leslie Malm, Lindsey’s mother, has stood at the marathon finish “since we were babies,” Lindsey said. But this year, still suffering from post-traumatic stress disorder from the bombings, she won’t be going back.

“She didn’t think, emotionally, she’d be able to handle going back,” Lindsey Malm said.

For a time, runners in the downtown area were still able to pick up their finisher’s medals — the coveted blue and gold pendants given each year to runners who complete the course — and in the immediate aftermath of such a tragedy, no one was going to deny medals to those who had come so close. And so the near-finishers got medals as well.

“The race coordinators clapped for me when I picked it up downtown,” said Grace West of Chevy Chase, who was among the hordes stopped on Commonwealth. “I wanted my medal for all my hard work, but it suddenly felt selfish and inconsequential to be concerned about it.”

For the most part, the runners who were stopped along the course were on their own when it came to reuniting with their parties and getting to somewhere safe — the degree of difficulty for which was multiplied by the fact few runners had cellphones, and even those who did soon discovered cell service was spotty at best.

“There was no cell service. Going on Facebook was the only way to get information or contact people,” said Rosenthal, the 64-year-old Bethesda resident. “It was the first day in my life I saw the value in social networks.”

Smith, the 44-year-old Annapolis resident, borrowed a phone from a stranger to text his wife that he was okay. A combat-hardened military man, Smith had only started running after surviving a helicopter crash and being encouraged to take it up as part of his physical therapy. Boston was going to be his one and only marathon.

But that day, shaken by what had just happened, he started walking, on legs that had just run 25 1 / 4 miles, toward his hotel three miles away. Encountering some race volunteers, visible by their yellow jackets, he told them how close he had been to finishing, and one of them pulled out an extra medal from a bag she was carrying and presented it to him.

“If I was a crier,” Smith said, “that would have done it.”

‘I feel an obligation’

In May 2013, after finishing up her finals at Shenandoah University, Hoffsis, the 25-year-old Rockville native, joined some friends in Boston and wound up making an impromptu dash down Boylston Street — traffic and all — covering that last half-mile and thus completing, if only symbolically, her Boston Marathon.

“It was awesome to be able to finish, even if I was surrounded by cars,” Hoffsis said.

But around the same time, the Boston Athletic Association made an announcement:

All 2013 entrants who were forced to abort the race but who were past the halfway point would be considered, at least for official purposes, finishers.

Thus did Ben Beach learn his consecutive-finishes streak was still alive, at 46 years and counting.

“That was a relief,” he said. “I appreciate them giving us the benefit of the doubt because all of us with the long streaks — we would have gotten across the finish line, one way or another, if the tragedy hadn’t happened.”

And soon thereafter, Jackie Ebert, a 49-year-old from Chevy Chase, opened a piece of e-mail from the Boston Athletic Association and found inside her extrapolated finish time: 4 hours 35 minutes. It wasn’t a time she was particularly proud of (she had qualified with a 3:54), but considering she had breathing issues and was running, by her standards, a terrible race that day — before being stopped on Commonwealth Avenue — she was grateful to receive the official confirmation.

“I wanted that crappy time because I know I was going to finish,” Ebert said.

Perhaps more significantly, the association had decided to make an extraordinary gesture to the 5,633 runners who failed to finish in 2013: They could return in 2014 without going through the typical qualification measures.

It was a no-brainer for most — a shot at redemption on a personal level, a collective statement of defiance in the face of terrorism on a civic level — but not for everyone.

“I had no interest in participating in any more large races — or really being anywhere with a ton of people,” said Shepherdson, the 42-year-old District resident. But after receiving the invitation, she said, “I changed my mind. I don’t like to live my life in fear, and I think it’s important to show strength for all those impacted by the events last year.”

“I feel an obligation to those who extended the invitation to see it through,” said Smith, the Annapolis resident. “Every time I run, I’m reminded that I’m fortunate I still can.”

All of them, assuming their bodies hold up and nothing else halts this year’s race, will have to deal with a powerful, personal moment — the moment they find themselves back at their 2013 end-points, at the intersection of glory and horror. Perhaps they will be visited by a rush of memories and emotions. But being marathoners, they will undoubtedly press on.

“I’ve thought about getting back to the point where I stopped — what that will feel like, just finishing those last 300 feet or so,” said Cotter, the Adams Morgan resident who could see the finish line a year ago.

“Doing the whole race, obviously, will be important,” he said. “But it’s not a 26.2-mile race for me. It’s only a few hundred feet.”