There is no evidence that account was true, Smith said.
Some reports have focused on the car, some on the suspects.
In one case, police heard that the suspects stopped at a particular shop and were captured on videotape. When police arrived, they found that the security camera had recorded over the footage that would have included the suspects, Smith said.
Other rumors have placed people resembling the sniper suspects at a Hagerstown convenience store and at restaurants in Halfway and Myersville.
Washington County Sheriff's Department Capt. Doug Mullendore said he hasn't heard of any sniper reports reaching his department.
But that can happen in well-publicized cases, he said.
"Normally, you do get some false sightings," he said. "People see a photo on paper and realize there's someone that might fit it. Ninety-nine-point-nine percent are not accurate - but you have to check them."
Smith said callers rarely try to mislead police.
"People are genuinely trying to be helpful," he said. "There's a lot of blue, older model Caprices."
The public is simply honing in on that model, Smith said.
"It's kind of like when you get a new car," he said. "You notice all the others like it."
Major Greg Shipley of the Maryland State Police said authorities were continuing to investigate the suspects and their trail in and around the metropolitan Washington, D.C., area, so tips are still welcome.
Smith said some tips that reached Hagerstown Police were passed along from the hotline and some came directly from the public.
Until authorities can fill in the gaps of what the suspects did and when, police can't rule out the possibility that they were in Washington or Frederick county before they were arrested.
"So far, we can't establish that they were here ...," Smith said. "I don't think that we'll know for sure until these guys start talking."
A restaurant in Halfway refused comment Tuesday on a published report that at least one of the alleged sniper suspects ate there the day before they were captured.
"We're not allowed to make any more comments," an assistant manager said Tuesday night.
The Washington Post reported Tuesday that the restaurant's manager said a waitress believes she served Muhammad sometime before 9 p.m. on the day before Muhammad and Malvo were arrested.
Neither the Sheriff's Department nor Maryland State Police were aware of any calls to go to the restaurant.
But that doesn't mean it didn't happen, Sheriff Charles Mades said Tuesday.
The restaurant would not have been required to call the Sheriff's Department to report a possible sighting, he said.
If federal agents were investigating witness reports of sightings, the agents are not required to inform the Sheriff's Department about those inquiries, Mades said.
It would not be unusual for local authorities to be kept in the dark about a federal inquiry, Mades said.
Staff writer Scott Butki contributed to this story.