The next morning, four others in Montgomery County were killed while doing mundane activities - pumping gas, mowing a lawn, sitting on a bench, vacuuming a minivan. A sixth victim fell that night in Washington near the county line.
"You never knew when and where the next shot would come, and it was so random," said former Montgomery County Executive Douglas M. Duncan, recalling a time when schools went into lockdown, motorists eyed white box trucks suspiciously and people felt nervous just pumping gas.
Relief came only after police arrested John Allen Muhammad and his teenage accomplice, Lee Boyd Malvo, at a Frederick-area rest stop Oct. 24, 2002.
Tonight at 9, Muhammad is scheduled to die for one of those 10 killings, that of Dean Meyers at a gas station in Manassas, Va. Prison officials in Virginia say he will be executed by lethal injection at the Greensville Correctional Center. The U.S. Supreme Court rejected a bid on Monday by Muhammad to stop the execution.
"I think it's justice," Duncan said. "I think he deserves it."
Though seven years have passed since the sniper attacks, vivid memories remain seared into the area's collective psyche.
"Every citizen, at some time or another, felt they might be the next person in the cross hairs of the sniper," said Maryland Attorney General Douglas F. Gansler, then Montgomery County state's attorney.
After Muhammad and Malvo were arrested, it emerged that the pair had spent time in Baltimore's Remington neighborhood, visiting a Subway restaurant and sleeping in their 1990 Chevrolet Caprice.
One day, Muhammad visited rare-book dealer Teresa Johanson at her shop not far away on 25th Street, asking whether she had any books in Arabic. "He had a certain intensity and a look in his eyes," she recalled Monday.
Johanson located a volume of lyric poetry in Farsi by a 14th-century poet named Hafiz. Muhammad told her he wanted to buy the book as a gift but left without making a purchase, she remembers.
"I want to thank you for all the trouble," he said on his way out. Johanson realized who he was after seeing his face on television.
When witnesses reported spotting white box trucks at sniper shootings, police began focusing on the ubiquitous work vehicles. So did the public. Alison Cuomo of Columbia recalled her panic as she drove to work in Washington and, stuck at a red light, realized she was surrounded by white box trucks.
"I'm sitting at the intersection, saying, 'Turn green, light, turn green,' " she said. "You suddenly have this massive paranoia when you see them."
For Cuomo, it became a "struggle" merely to be outdoors. "I thought twice about going to a pumpkin patch, which is silly," said the 34-year-old Web editor. "But you couldn't help question every move you were making. You had no idea when they were going to strike next."
Filling stations took on a sinister air after sniper victims were shot while pumping gas. Some people adopted survivalist tactics, Duncan said. They would insert the nozzle in their tank, then lie flat on the seats or floorboards until the tank was full.
Duncan, as county executive, was involved in efforts to catch the killer or killers. But he, too, was scared.
"I moved pretty quickly when I was walking places," he said. "Part of my job was to be out in the public and reassure the public that things were safe and we needed to keep doing our normal routine."
Underneath his calm veneer, he worried. "At some point," he said, "I sort of accepted that, hey, my face is out here. They know who I am, I'm easy to find. If they're going to shoot me, they're going to shoot me. You come to accept that and think, I've got a job to do, and just do it."
Adding to his stress was a growing sense that the snipers were responding to public comments made by him and the county police chief, Charles Moose. Early on, authorities offered parents tips on how to keep their children safe - and feeling safe.
Then on Oct. 7, a 13-year-old boy was critically wounded after being dropped off at his middle school in Bowie. Looking back, Duncan said, "I do think they went to the school and shot the kid because we made a big deal about safety for children."
That shooting filled parents with dread. Some stopped letting their children walk to school or kept them home for a time. Schools became fortresses, canceling outdoor activities and closing window blinds.
Fairfax County announced that sporting events would be moved south to Richmond, and Duncan suspects that decision may have played a role in another shooting. In that case, a 37-year-old man was wounded in a restaurant parking lot in Ashland, Va., north of Richmond, ending a five-day lull in the sniper attacks.
"I think they went there just as a way to say, 'Hey, you're not safe here, either,' " said Duncan, now senior vice president of business development at CivicUS, a firm that advises local governments on executive management.
The last killing came Oct. 22, 20 days after the first. What started in Montgomery County ended there when bus driver Conrad Johnson was shot on his empty bus.
Two days later, authorities arrested Muhammad, then 41, and Malvo, then 17, at a rest stop off Interstate 70 near Myersville. Still, Duncan refused to relax; "you didn't want to announce you'd caught them for fear they weren't the ones," he said.
All day on Oct. 24, federal ballistics experts worked to connect Muhammad and Malvo to the sniper shootings. That evening Duncan heard cheers through the wall of Chief Moose's office.
"That's when everybody else breathed the sigh of relief," Duncan said. "Moose came out and told me, 'We got 'em.' "
For a year after the sniper attacks, people would approach Duncan on the street and thank him. "Many of them would start sobbing in front of me, just uncontrollably."
Recently he has heard from some "soccer moms" who were upset by the possibility that Muhammad might avoid execution through a judicial stay. "People I would not have thought were death penalty supporters really wanted justice done and wanted him put to death," Duncan said.
Baltimore Sun reporter Jacques Kelly contributed to this article.