With the manhunt continuing for a sniper linked by police to 10 shootings in the Washington area, a weekend without a new attack brought a mixture of relief and dread to people who went about normal activities with foreboding yesterday, wondering whether the bloodshed will resume.

Even as they shopped, took their children to pumpkin patches and attended football games, thoughts of the elusive sniper remained in the forefront of people's minds.

"People are very anxious about what the coming week may bring," said Sean T. Connaughton (R-At Large), chairman of the board of supervisors in Prince William County, where one of eight victims killed by the sniper was shot at a gas station Wednesday night.

"They don't really know what to expect," Connaughton said. "While in general they're very confident that at some point the individual or individuals will be apprehended, the issue is how much more damage is he going to cause."

In Montgomery County schools, a Code Blue will remain in effect today, meaning no outdoor activities will be allowed for students, officials said. Similar restrictions will remain in place in Prince George's County schools, where all athletic events and practices have been suspended.

Yesterday, a tip hotline set up by authorities was flooded with calls after police on Saturday night released composite images of a white box truck that witnesses reported seeing near more than one of four fatal shooting scenes in Montgomery on Oct. 3. Authorities said they believe the truck had damage to its rear and had dull, oxidized paint, suggesting that it is an older vehicle.

At a news briefing yesterday, Montgomery Police Chief Charles A. Moose said he hopes the image will prompt someone to recall the truck. "Someone that does repairs may have had a truck like this brought to them to have the rear door repaired," he said. "Perhaps someone has had this vehicle painted. So we would like to talk to any number of different people that may somehow be associated with this vehicle."

Moose also said authorities are preparing composite images of a different vehicle, a white Chevrolet Astro van, that some witnesses reported seeing Friday morning near a Spotsylvania County gas station, where the sniper's most recent victim was fatally shot.

"We want it to be real clear that the two vehicles are separate," Moose said on CNN's "Late Edition" yesterday. "The Astro van is something we've gotten from witnesses [in Spotsylvania]. We're looking for that vehicle."

As law enforcement officials across the region remained on an urgent state of alert yesterday, police continued to respond in overwhelming numbers to reports of suspicious activity that in the past might have attracted only a few officers.

A flurry of excitement was touched off late yesterday afternoon in downtown Rockville when the sound of a gunshot was reported. Police raced to the area, near Monroe and East Jefferson streets, and their arrival and the clatter of a hovering helicopter drew residents into the streets from a large apartment building and nearby houses.

"It was a loud shot," said one resident, Maura Magnier. "It could have been a gunshot." Glenn Looper was watching television at home about 4:35 p.m. when he "heard something that sounded like a shot." Ten minutes later, he said, he heard the helicopter. Derrick Krellen said, "We were walking through the cut in the woods [when police arrived] and they pulled this machine gun on us."

By 6:15 p.m., said Montgomery police spokeswoman Joyce Utter, the search for a victim or assailant had ended, with nothing suspicious found.

Fearing another sniper attack, a regional law enforcement task force has developed a response plan that involves choking off roads and creating traps for the shooter.

The plan already has been put into action about a half-dozen times, sparked by shootings linked to the sniper and by other incidents that turned out to be unrelated. Until the sniper is arrested, police said, they intend to react initially to all reports of shootings as if they were attacks by the sniper.

On Saturday night, for example, a woman was shot by an unidentified assailant on Old Branch Avenue in Suitland. The nearby Capital Beltway was immediately closed, and Virginia state troopers kept watch on the Woodrow Wilson Bridge until investigators concluded that the slaying of Irina Hans, 26, was unrelated to thesniper.

"They did initially treat this as though it was a sniper situation until soon afterward it was proven not to be," said Cpl. Robert Clark, a Prince George's County police spokesman. "Until the shooter is caught, we'll have to evaluate every shooting death that comes in."

Authorities across the region said residents can expect such urgent responses by police as long as the sniper is on the loose.

"In any shooting, we're going to try to catch the bad guy," said Dennis Mangan, a Prince William County police spokesman. "But now we've got a guy who is terrorizing the whole metro region. If we had these resources for every shooting, we'd be shutting down roadways more often."

Police still are not certain whether they are looking for a singlesniper or a team of shooters. A military official said yesterday that the Army's Criminal Investigation Command has been asked to search records of personnel discharges for a lead in the sniper case.

The 10 shootings since Oct 2 -- five in Montgomery, two in Spotsylvania and one each in Prince George's, Prince William and Northwest Washington -- have rattled the Washington region and heightened prosaic activities with a sense of danger.

"A lot of people are calling prior to coming and asking what kind of security we have," said Gayle Marrocco, manager of Leesburg Gardens, which features pumpkin patches, hayrides and apple bobbing. "School groups are canceling or re-booking."

Montgomery County Executive Douglas M. Duncan (D) said yesterday that the public is acting cautiously and calmly.

"People are going about their normal routines as best they can," he said on CNN. "They're going to work. They're going to school. They're going shopping. They're doing those kinds of things in their normal routine that they usually do, except they're a little more cautious, a little more vigilant, a little more observant than they have been before."

But at Gaithersburg's Lake Forest Mall, many shoppers said they were steeling themselves for the week to come.

"I'm to the point where I turn on the radio and I expect to hear something," said Nichole Fanter, 29. "And this week I'll probably be the same thing as last week: sitting on the edge of your seat every time you click on the news."

Some said they felt emotionally drained.

"I think lots of people are worried about next week," Dave Holch, 53, said as he shopped. "It's been a rough 10 days -- for children, everybody in the region. With it being so quiet this weekend, who knows what these days ahead are going to bring?" 

One official who refused to fret over possibilities was the Montgomery County police chief.

"We won't make any assumptions about any kind of pattern," Moose said. "I never approach Monday morning with a sense of dread."

At the Pentagon City mall, two women carrying their purchases walked together and shared what they called their "getting gas stories." Of the sniper's 10 victims, four were killed at gas stations.

"For me, I was nervous," said Rachel Slemons, 34, of Arlington, who recalled watching her gas gauge drop as she drove along Interstate 66 and refused to stop. "I was looking around at the rooftops, and lo and behold, a white van pulled up in the gas station. It's definitely nerve-racking."

Shirley Parkhurst, a District tour guide from Alexandria, said she had noticed the absence of attacks this weekend.

"I have mixed feelings for the coming week," she said. "To be honest, I don't know what to feel. I'm cautious above all.

"You wonder if the past is prologue."

Staff writers David Cho, Christian Davenport, Hamil R. Harris, Chris L. Jenkins, Leef Smith, Eric M. Weiss and Josh White contributed to this report.