Two bombs killed three people and injured more than 170 after exploding near the finish line about two hours after the first wave of runners had completed the race on April 15. The dead included an 8-year-old boy there to watch his father run; his mother and sister were badly hurt by the explosions.
Authorities later killed one of the suspects in a shootout and captured the other.
Facebook employee and dedicated runner Jessica Shambora described how a "beautiful day" turned terrible in a blog post. After crossing the finish line, she went to pick up her bag when the bombs exploded. "Most of the runners were in a post-race daze, cold and stumbling around and suddenly terrified," she wrote on April 15.
She found her boyfriend and a group of friends, then returned to where they were staying in Cambridge.
"I am still in shock and not sure I have much to add at this point. Just want to let you know and share my sadness. Despite the tragedy I will still try to remember this as a day of great courage, from the runners to the first responders," Ms. Shambora wrote.
She told the Almanac that she and her boyfriend ran the marathon "because we are runners. We both qualified over the past year and a half and, of course, Boston is a big goal for many runners."