"I'm telling you, it ate at me," she said. "I was like, 'You mean to tell me you couldn't catch these guys beforehand?'"
Dennis Henigan, legal director of the Brady Center to Prevent Gun Violence, credits the work of Johnson and relatives of other sniper victims with so far keeping the legislation from clearing the Senate.
For her part, Johnson said, she hopes that by telling her story, she gave pause to some lawmakers who otherwise might back the legislation. But it also brought her a small measure of comfort.
"Honestly, it is helping us," Johnson said. "Of course, the pain will forever be there. The loss will forever be there. But for us, it will help if my husband's death is not in vain."
Margaret Walekar, an obstetrics nurse, has skipped some gatherings of her extended family in Maryland, not wanting to ruin the mood with tears that spill without warning.
What is most difficult, she said, is thinking about the future she had planned with the man who became her "soul mate" after their arranged marriage. After years of working as a convenience store owner, newspaper distributor and cabdriver, her husband planned to retire early. The Walekars were going to start splitting their time between Maryland and India, from which they emigrated in the 1970s and where they recently bought a house for visits.
"Now, all those plans are destroyed," she said. "In one minute, everything is gone."
The couple's daughter, Andrea, 25, was too upset to continue attending the University of Maryland, but she managed to graduate in May after finishing her studies from home. Their son, Andrew, 24, stopped going to church.
"He thought his dad was a very good person," she said. "He thinks, 'Where was God? Why didn't he save him?'"
The victims' families and friends have changed their daily routines and restructured their lives. But reminders of the shootings cannot be avoided.
Tim Sheehan, executive vice president of the Boys & Girls Clubs of Greater Washington, was at a meeting recently in Manassas, Va., when someone mentioned that Muhammad was being held two blocks away. Sheehan thought immediately of his friend, Buchanan.
"I thought, 'God, you can't get away from it,'" said Sheehan.
Charles-August Charlot thinks of his cousin each time he passes near the shooting site in Northwest Washington. Often, he visits Pascal Charlot's grave.
There, the Silver Spring man reminisces about how his cousin called him "Preacher" because he was prone to doling out advice. He recalls how the two men, one a draftsman and the other a carpenter, would help each other with house projects.
Casting back further, he remembers growing up together in Haiti, where his cousin would get the best grades in Greek class even as he put off studying until the last moment.
On a recent trip to the cemetery, Charlot, 67, looked down at the gravesite and shared the news that he had become a grandfather.