Rockville, Md. ? Virginia authorities on Friday arrested a man accused of misleading investigators in the Washington-area sniper shootings by falsely describing an olive-skinned man and a cream-colored Chevrolet Astro van with a burned-out taillight at the scene of one killing.

Matthew Dowdy, 37, of Falls Church, Va., was arrested by Fairfax County, Va., police Friday afternoon and charged with making a false statement, said police spokeswoman Isabel Benemelis. The charge carries a maximum penalty of six months in jail.

Later Friday, Montgomery County police said authorities were examining a shell casing found inside a white box truck at a car rental agency near Dulles International Airport in Virginia.

Montgomery County police spokesman Derek Baliles says it is unclear if the truck has anything to do with the sniper investigation. The rental agency contacted police Friday evening, said Capt. Nancy Demme, a Montgomery County police spokeswoman.

Police are still asking the public to provide them with information about white box trucks as previously described, the spokesmen said.

Baliles also says police do not expect to have any further information about the truck or the shell casing until Saturday morning.

Authorities began doubting Dowdy’s story what had initially seemed a good break in the frustrating case after comparing it with accounts from others who saw the fatal shooting of an FBI analyst Monday night in a shopping center parking garage.

Dowdy went before a magistrate Friday evening and was ordered held without bail at the county jail until a Monday arraignment.

Eleven people have been shot in the sniper attacks since Oct. 2, and nine have died.

Expanded investigation

As a lull in the shootings stretched into a fourth day Friday, investigators revisited crime scenes and acknowledged they had to expand a search area after deciding that Dowdy’s account was false.

Fairfax County officers combed an area across the highway from the Home Depot store in Falls Church where Linda Franklin was shot Monday as she loaded packages into her car. Before the area defined as a crime scene was expanded, reporters and bystanders had been allowed to tramp all over the area now being searched.

“Law enforcement in America is a learning institution,” said Montgomery County Police Chief Charles Moose, who is leading the multi-jurisdictional investigation. “We adjust and we improve.”

New details about the investigation were few as the sniper took his longest break since the shootings began. Before Franklin’s killing, the greatest time gap between shootings was three days and the previous long gaps included weekends.

Moose didn’t want to speculate on the quiet period for fear of tempting the killer to prove authorities wrong.

“Any day without violence remains a good day,” he said.

Lull in shootings

But others read some meaning into the killing gap. Tod W. Burke, an associate professor of criminal justice at Radford University in Virginia, said the lull is likely temporary.

“I don’t believe this guy has an emotional cooling-off period,” said Burke, a former Maryland police officer. “I think he or they is still ready to go. The only thing holding them back right now seems to be the police response … they’re reloading and refueling I mean mentally reloading and refueling.”

James Alan Fox, a professor at Northeastern University’s College of Criminal Justice, said the one prediction that can be made about this killer is that he’s unpredictable.

“The hiatus that we’ve just seen … could mean several things,” he said. “Maybe he’s not feeling well. It was pretty rainy there. Maybe he’s under the weather. Serial killers get sick, too.”

Until now, the killer has been seen as a “weekday warrior,” Fox said. If he does strike this weekend, it might be to prove again that he cannot be classified, categorized or profiled.

“It could be that he’s just planning his next move,” Fox said. “Maybe he feels he needs to do some extra homework.”

Terrorism links?

U.S. investigators are questioning terrorism suspects at Guantanamo Bay in Cuba about whether they had any information about the sniper attacks, a law enforcement official confirmed Friday, speaking on condition of anonymity.

The official characterized the interviews as an effort to cover all possible investigative avenues, adding that officials do not necessarily believe al-Qaida might be responsible for or even knowledgeable about the shootings.

Meanwhile, Moose said the investigation into whether a Sept. 14 shooting at a Silver Spring beer and wine store is connected is continuing.

Police responded to numerous false alarms, including a report of two camouflage-clad men in a white van Friday who turned out to be bowhunters. A report of a shattered window at an office building turned out to be “hot/cold dynamics,” Moose said.

Two shooting victims are scheduled to be buried Saturday.

Dean H. Meyers, 53, of Gaithersburg, who was killed Oct. 9 at a Prince William County gas station, will be laid to rest in Pottstown, Pa. Pascal Charlot, 72, gunned down Oct. 3 while standing on a Washington street corner, will be buried in Washington.