Residents say the small Friendship Heights neighborhood of Brookdale is a community with the pluses of both city and suburban living and few of the minuses. But one minus could turn out to be a big one: the development plans of the giant insurance company whose sprawling headquarters building and parking lots adjoin the neighborhood.

Homeowners in Brookdale believe the Government Employees Insurance Co. (Geico) is buying property in the neighborhood through trustees so that the company's name will not appear in land and tax records. They fear the company has long-range development plans that may include demolishing homes and building offices and parking lots.

Friendship Heights and Brookdale community leaders, however, are among the most sophisticated and tireless in the Washington area in dealing with developers and the Montgomery County government over unwanted construction.

"We can smell a bulldozer a mile away," said Evelyn Aikman, who lives next door to a house she is convinced belongs to Geico.

Brookdale residents have searched land records and questioned Geico officers, and say they found company representatives evasive and uncooperative. Company representatives say they consider the specifics of Geico's real estate holdings confidential.

The neighborhood believes it has "a historic commitment from Geico from the 1950s," according to Campbell Graeub, a member of the citizens association and a longtime resident. Brookdale homeowners supported the insurance company's plans to build its headquarters next door in return for a promise that it would "always maintain the buffer" of trees and lawn that separates the Geico complex from Brookdale, he said.

"Now they're going back on their agreement," Graeub said.

Brookdale resident Ken Orski said he suspects Geico is assembling land for future commercial development. "I believe this is the ultimate scenario," he said, "especially because they are doing this so surreptitiously."

Geico spokesman Walter Smith said the company made no agreement with the community in the 1950s. He said that if the company plans any expansion in the future "we would discuss that plan or those plans with our neighbors here and other parties interested in such plans."

The insurance giant is trying to safeguard its interests "and protect housing values" in the neighborhood by purchasing homes, Smith said. "We've been buying property adjacent to our offices for the past 25 years" and will continue to purchase nearby homes. "As houses become available, if we feel they're at a fair market price, we would take advantage" of the opportunity to buy them, he said.

The number of properties "we hold and how we hold them is confidential to Geico," Smith said. He declined to identify the houses Geico owns, saying, "I don't think there is anything to be served" by being specific.

He said, however, that after the company buys a house in Brookdale, it renovates and then leases it, "preferably to quality tenants." Geico charges about $1,500 a month rent, he added.

Trees and a strip of grassy land still form a buffer to separate the Geico grounds from Brookdale. Under an agreement between Geico and Montgomery County, the county maintains a small park on Geico property adjoining the buffer.

David Sheridan, who has lived in a Geico-owned house in Brookdale since 1969, said he paid rent directly to Geico for several years before the company set up a separate organization to collect rent. He said he still calls an office at Geico when the house needs repairs.

"We tried to buy this house but they weren't at all interested," Sheridan said of Geico. Influenced by the opening of the Friendship Heights Metro station and rising real estate prices, Brookdale rents generally have more than doubled in the last two years, he said. One consequence of higher rents is "a higher turnover" of tenants, he added.

Although Geico declined to identify the houses it owns, Brookdale homeowners are confident they have pinpointed some of them. The entire western side of Cortland Road, which adjoins the insurance company's property, has been purchased by Geico over the past 20 years or more, according to the homeowners. Land and tax records list the Riggs National Bank as trustees owning the property, but do not name the owner for whom the land and houses are being held.

The trustees for at least eight other homes purchased on other neighborhood streets since 1984 are Rex S. Garrett, president of Eagle Realty Corp. of Virginia, and his wife, Jacqueline Garrett.

Garrett, whose office is in McLean, said he is the trustee "for an investor who wishes to remain anonymous." A Riggs spokesman said confidentiality "is a key component" of the bank's trustee agreements.

The homes in Brookdale were built between 1939 and 1941, and "not one house is exactly the same" as another, Graeub said. There are no sidewalks and very little traffic passes through the neighborhood, thanks to a number of dead-end streets, he said.

Residents prize Brookdale because it is within walking distance of the Metro station, stores and restaurants but is a tree-shaded upscale Montgomery County neighborhood, according to Marvin Ott, a community leader.

He said homes in the neighborhood are in great demand. "Not a week goes by" without flyers being distributed in the neighborhood by real estate companies trying to sell houses there. Property values have been rising rapidly, with most homes now priced in the $275,000 range. Some, however, have sold for as much as $395,000.

Brookdale owners said they started to worry early in the autumn of 1986 when a number of homes were purchased and Garrett was the trustee listed on all the deeds.

Ott called a Geico vice president to discuss "concern in the community that Geico was buying the property" and asked for a meeting between residents and company leaders to discuss the company's plans. He said the official first denied the company was buying the property, but in a later telephone conversation agreed to meet with the homeowners. During the session, Geico officials "said, 'We don't talk about our properties,' " Ott said.

The 26-acre Geico headquarters site is zoned for single-family residential development. The county zoned for commercial development the land under the 508,000-square-foot building; the two parking lots were built with a zoning exception granted by the county. The county master plan for the area says that no further commercial or office development or special exceptions should be permitted on the Geico property.

But a traffic study prepared privately for Geico earlier this year said, "It is likely ... that the future will see additional development at Geico." The company parking lots "obviously will not remain as surface parking lots and will ultimately be redeveloped," according to the study.

In urging the county to build an 80-foot-wide road between Geico's property and the adjoining Woodward & Lothrop Co. property, Geico President W.B. Snyder said in a letter last April that "with many underdeveloped properties in the area, development currently under construction and proposed construction," the wide roadway will be needed.

The road would extend Friendship Boulevard from Willard Avenue to Jenifer Street at Jenifer's junction with Western Avenue. Construction is to begin in April 1990.

"I'm quite certain there will be a lot more discussion" about the road plans, said Robert C. Merryman, chief of the division of transportation engineering for the Maryland-National Capital Park and Planning Commission, which does most of the planning for Montgomery and Prince George's counties. The current plan calls for a 40-foot-wide road, the width many homeowners favor.

Neal Potter, chairman of the county council's transportation and environmental committee, said that if Geico wants to expand, "considerable reevaluation" of the county's master plan would be required. He said he believes "the citizens will be very negative."

Real estate interests, however, "put a lot of money into the last election and got a somewhat more friendly county council," Potter said.