Every day seems busier than the last at Howard Grant's Guardian Alarm Sales Inc. in Bethesda. "This is our greatest year ever," says Grant. "We hope to crack the $300,000 barrier this month alone."

Orders are backed up six weeks even though Guardian has 10 crews on the road installing security systems that begin at $600 and can cost as much as $15,000.

The sharp rise in homeowners' fears follows the fatal shooting earlier this month of physician Michael Halberstam during an encounter with a burgler in his Northwest Washington home. Among Guardian's new clients are nine homes on Battery Place NW -- all neighbors of the slain cardiologist.

The arrest of a suspect in the Halberstam case -- who police say may have committed hundreds of burglaries in the area -- apparently has done little to quiet those fears. Officials at many area banks say they have run out of safety deposit boxes where silver and other valuabales can be stored for as little as $12 a year.

At the Maple Avenue branch of United Virginia Bank in Vienna, all 1,400 safe deposit boxes have been rented, and there is a waiting list several hundred names long, a bank executive said.

"People are going from one extreme to the other," says Claudine Porter, an officer with the Prince William County Crime Prevention Bureau.

In the Willowbrook subdivision of Prince William, she says, there were so many burglaries that residents "took to arming themselves with baseball bats and confronting any strangers they saw."

"Everyone is scared," agrees Fairfax County Supervisor Thomas M. Davis III, whose home was burglarized last month.

Davis and his wife, Peggy, were awakened at 3:30 a.m. by a noise in the kitchen. Davis rolled a football down the hallway toward the kitchen. Then he dialed the Fairfax police for help.

To his chagrin, Davis was put on hold. The operators were busy coping with other callers with similar emergencies.

"I was surprised, but I'm not complaining," Davis said. "The police came in a few minutes." Meanwhile Davis's burglar had already fled out a back door.

The Ravenwood Civic Association which represents 50 families in a frequently burglarized subdivision of expensive homes in eastern Fairfax, recently held it annual Christmas party. But before the party began at a resident's home, association president Dana Mallett felt obliged to notify the Mason police station to ask officers to keep close watch on the other houses while residents were away.

The association has conscripted what Mallett calls its corps of "nosey busybodies" -- elderly residents who during the day, keep an eye peeled for strangers in the neighborhood.

In Great Falls, a secluded area in northern Fairfax where an average of one out of 10 homes is burglarized annually, the citizens association is installing signs for would-be burglars at seven major entry points. The signs read: "Warning: Homes in Great Falls Are Protected by Intergrated Alarm Systems."

One of the many Great Falls residents who decided to install alarm systems was Bernard C. Welch, alleged thief and murder of cardiologist Halberstam.

Area residents who don't have a safe deposit box or vault have to improvise hiding places, and they do so with mixed results. Robert Law of the Prince Georges County Police Department had heard of nearly everything: "People hid valuables in refrigerators, in the ice compartment of freezers. They have sealed valuables in plastic and stuck them inside the tanks behind their commodes. Under the mattress is the worst place -- everybody looks there."

A frequent hiding place is a cookie jar, but Prince William's Porter says it is one of the worst choices. "Most of our burglers are juveniles," she said. "And cookie jars are one of the first places they look."

One wealthy, 81-year-old shut-in, who had been burglarized once at her Loudon County home, believed she had the answer. She hid her diamonds in the bottom of a 15-gallon fish tank.

A couple of days later, they were gone and, frantically, she called the police.

But burglars had not paid her a second visit. The fish had eaten the diamonds. CAPTION: Picture, Many area banks have run out of safety deposit boxes where silver or other valuables can be stored for as little as $12 a year. By James M. Thresher -- The Washington Post