"Of course, we were all dumbfounded," said Vernon, now a senior policy analyst at the University of Maryland Center for Health and Homeland Security. "There was no ransom demand, there were no statements, nobody was taking responsibility for the attacks. ... Normally when somebody does something like this, they want to take credit."
The first communication came on Oct. 7. Iran Brown, 13, was arriving at Benjamin Tasker Middle School in Bowie when he was shot in the torso.
This time, police found a message at the scene: The death card from the tarot deck, inscribed with a note. "For you Mr. Police/Code: 'Call me God'/'Do not release to the press.'"
LaRuffa, who had spent 10 days in the hospital after the September attack, followed the news from home. His shooting remained unsolved; while friends suggested it might have been the work of the sniper terrorizing the area, he didn't think so.
His attacker had walked up to his car, shot him several times at close range and stolen his laptop computer and $3,500 in cash from the restaurant. Whoever was killing people was using a single bullet fired from a distance.
In fact, investigators would learn, Muhammad and Malvo had staked out LaRuffa at his Margellina Restaurant before the attack. They were using his money to finance their killing rampage. From Oct. 9 through 14, they killed three more people, all in Virginia.
Snider, grieving for her brother, winced at every new report.
"The whole thing was so surreal and so sad, and for them to take so many lives in such senseless ways," she said. "They were all hardworking people just going about their daily lives.
"Just watching other people die as the week went on, that was very difficult, to know that other families were going through what we were going through."
Duncan, the former county executive, says he had a responsibility to present a face of calm to the community as he appeared at public meetings, news conferences and funerals.
At the same time, he said, "When I went home early in the morning, I didn't dawdle. I scurried into my house. You're on TV a lot, and you know they're watching because of their communications. You just assume that you've become a bigger target."
He speaks with pride about the courage of the community, and cites an example.
"We didn't want school crossing guards out there with the uniforms and the vests standing there as targets," he said. "So we pulled them out, but we asked for volunteers. And we had several hundred people come forward and say they were willing to help kids cross the street, help kids get to school, knowing that they could be a target."
While there appeared to be no end in sight to the shootings, investigators soon caught a break. They identified a fingerprint at Benjamin Tasker Middle School as Malvo's, learned of his relationship with Muhammad and found that Muhammad had registered a blue 1990 Chevrolet Caprice in New Jersey. Police named the suspects, described their car and called on the public to report any sightings.
Early on Oct. 24, a refrigerator repairman from Pennsylvania spotted the Caprice at the I-70 rest stop near Myersville and dialed 911. Police swarmed over the scene and arrested the pair without incident.
Muhammad and Malvo were charged, tried and convicted of six counts of murder in Maryland and two counts in Virginia.
During Malvo's trial in Maryland, he described the pair's plans to take their terror to Baltimore, where they planned to kill a pregnant woman and a police officer. At the police officer's funeral, he said, they planned to lay improvised explosive devices, similar to the roadside bombs used by insurgents in Afghanistan and Iraq, to cause more deaths.
In Maryland, Muhammad and Malvo were each sentenced to six life terms without possibility of parole. In Virginia, Malvo was sentenced to life in prison without possibility of patrol. Muhammad was sentenced to death.
Snider attended the trials and was present Nov. 10, 2009, when Muhammad was executed. She described it as "very medical."
"I didn't expect closure," she said. She says she and her family have decided to focus on the positive: her brother's love for them, and for life.
She says he was committed to his community, where he volunteered with the Boys and Girls Clubs and Crime Stoppers. Her family has established a foundation in his name that continues to award scholarships to young people.
But as Snider tries to look forward, she finds that each new shooting in the news — at Virginia Tech, at the "Batman" movie premiere in Aurora, Colo. — freshens the pain.
"I wish there were more we could do in gun control," she said. "I was so devastated when the assault weapon ban expired [in 2004]. ... If it could happen to us, it could happen to anyone. I just feel like somebody else is going to get that knock on the door."