Concerned about a spate of robberies in the Waldorf area, the Charles County Sheriff's Office will hold three robbery prevention seminars this week. The sessions will include advice to businesses to post signs asking patrons to remove hats, hoods, headgear and sunglasses -- common items would-be robbers use to conceal their identity.

The tactic, conceived by sheriff's deputies who have seen the number of robberies rise recently, is meant to dissuade would-be robbers from entering businesses and to call attention to those inside businesses who don't comply, said Capt. Joseph C. Montminy.

"It's just another way to try to slow these guys down," Montminy said.

The free seminars, which are scheduled for 7 p.m. tomorrow and Wednesday and 10 a.m. Thursday at the Waldorf Jaycees Community Center at 3090 Crain Hwy., will address the rise of armed and unarmed, or "strong-arm," robberies.

Although the number of both kinds of robberies is down slightly for the year in the county, authorities have seen the number of such crimes spike in a relatively short time.

In September, the county saw 13 robberies, many at the end of the month. By October, the number had risen to 19, said Kristen Adkins, sheriff's office spokeswoman.

"For our community that's a lot and, like any other crime, when more robberies happen in a brief time, we start looking for possible connections between the cases," Adkins said.

Montminy said it is unclear how many of the recent robberies were carried out by the same person or group of people, but "it's hard to believe that a great number of those may not be related."

Detectives believe a group of people could be involved, Montminy said.

"A lot of times, there's more than one person involved," Montminy said. "The victims may not see everyone in the group. They may see the person with a gun, but there may be someone else at the door or in the getaway car."

Montminy said a variety of robberies have occurred. Victims have included bank tellers, store clerks and people in parking lots. The street robbers "seem to be younger kids, more often than not."

He said the robbers have picked Waldorf because it is the most populated area of the county and because it is on the Prince George's County border, allowing a quick getaway. "It's not that it's a crime-ridden area. It's just a matter of logistics. And bad guys know that."

Montminy also said robberies and thefts tend to increase during the holiday season.

"Businesses have more money; people need money," Montminy said. "Every year, and this year is no exception, we put together an enforcement effort in which we put more deputies on the street, and we typically do a mixture of covert and overt operations."

Recognizing that a lot of the robberies are "coverups," in which robbers hide their identities before entering a business, the Sheriff's Office began handing out fliers recently.

"We're serious about security," reads the sign, which is to be posted at the entrances to businesses. "We ask that you remove your hats, hoods, headgear, sunglasses before entering this business."

Authorities believe that with the notices, store employees and patrons will closely watch any patrons who do not comply with the request.

"People will pay attention to them more," Montminy said. "If the clerks or the other patrons pay attention to him more, he may decide to get out of there."

Among the recent robberies for which the Sheriff's Office is asking for the public's help:

* At 7:09 p.m. Nov. 2, a robber believed to be a teenager entered the Safeway gas station in the 3100 block of Marshall Hall Road brandishing a handgun and demanding money. The robber was wearing a skull cap, a black jacket with a hood and a white T-shirt covering his face, according to the Sheriff's Office. The clerk complied with the robber's demand for money before the robber fled.

* At 7:20 p.m. Oct. 15, two people entered Checks Cashed in the 12500 block of Mattawoman Drive and confronted the two clerks, a 57-year-old man and a 50-year-old woman, both of Alexandria. The assailants shot the man and struck the woman with the gun before fleeing with the money they demanded.

The man was flown to Prince George's Hospital Center with non-life-threatening injuries, and the woman was treated and released at a local hospital.

The robbers were described as men wearing dark masks and gloves. One is between 5 feet 8 inches tall and 5 feet 10 inches tall, and the other is 6 feet tall.

Charles County Crime Solvers offers rewards of up to $1,000 for information that leads to an arrest or indictment. Anyone who has information about the robberies or any other crime in Charles County may contact Crime Solvers at 301-932-6909 or 800-673-2777. Callers may remain anonymous.

Montminy said he does not think law-abiding residents will mind the new security policy at some businesses.

"We think that our county residents won't mind taking their hat off or pulling their hood down," Montminy said. "We also think the businesses won't mind. It seems like a reasonable thing to ask people to do, and if we prevent a couple of robberies, it's well worth it."