Three years ago, some Pittsburgh attorney nobody here had ever heard of bought two farms outside this decaying Eastern Shore fishing village for just over $1 million. It raised a few eyebrows -- considering he paid at least four times what people here thought the land was worth.

As it turned out, things were just getting interesting. During the next few months, the man kept right on buying: first some village lots for $75,000 (about three times more than anyone here would have paid for them), then a small farm for $85,000 (twice its estimated value). Then, still more farms and more village lots.

Suddenly, the 150 or so Oyster residents realized that one William M. Robinson, 41, an attorney in the Trusts and Estates section of the prestigious Pittsburgh law firm of Reed, Smith, Shaw & McClay, had spent just under $3.3 million for 2,204 acres -- most of the land in and around Oyster. The purchases made him one of the Eastern Shore's largest landowners.

And its biggest mystery.

Why, everyone here wants to know, does Robinson want to own Oyster?

You won't get much of an answer from Robinson, who has limited himself in the past to vague assurances -- almost always given through his own attorneys or agents -- that he is buying the properties with his own money and for his own use. In keeping with that practice, Robinson declined to be interviewed yesterday.

Such assurances don't wash in Oyster. Locals note that that's exactly the same line used by Robinson's real estate agent, who told a couple of property owners that he was buying their land for his own use -- and then four months later transferred the lots to Robinson.

So Oyster residents, who naturally are suspicious of an outside world that has ignored them for centuries, have developed their own list of groups or industries they suspect Robinson is fronting for, and it reads like a 20th Century Who's Who of controvery: the Moonies, Arabs, oil companies, real estate developers, conservationists, maybe even the Russians.

There's only one thing for certain. Nobody here really knows.

"My son says I shoulda made that a condition of my sale: what he's gonna do with my land," says Ray Newman, a farmer who sold 287 acres to Robinson in July for $850,000 -- a price he estimated was at least twice the going rate for Eastern Shore farmland. Then he adds: "Might be some offshore oil project."

"Everybody in the county is scratching their head," says Northampton County Administrator R. Keith Bull. "But this is America, and when you have a willing buyer and a willing seller, there's not much you can do about it."

Bull, it seems, is one of only a handful of Northampton County residents ever to meet Robinson face to face. For a while, it looked as if not even that meeting would occur, according to County Supervisor Wade Fitzgerald.

"We'd been trying to get him to meet with us over some landfill problem but it seemed like we could never get it arranged," said Fitzgerald. All that changed after county officials threatened to condemn some of Robinson's newly acquired holdings, he said. "Then he came down here to meet with us."

Not in Northampton County, Fitzgerald notes with amusement, but in Norfolk, across the 17.6-mile Chesapeake Bay Bridge-Tunnel that costs $9 each way for a passenger car to cross.

Even though the county managed to straighten out the landfill problem for the time being, no one learned anything else about what Robinson's plans are.

"Only thing he'll tell us is he's just buying for the fun of it," he says. Then he wonders about how many times -- if ever -- Robinson has visited the county. "Could be he has been here and nobody knew who he was," Fitzgerald finally ventures.

Robinson-speculating has become a full-time occupation in Oyster and elsewhere on Virginia's Eastern Shore, a low, sandy and isolated penninsula about 125 miles as the crow flies east of Washington and more than 200 miles by car. County officials enter each purchase on a chart, kept chronologically since the first purchase in July 1979. Then each parcel is colored in on a large-scale map of Oyster and the surrounding community -- all with an eye to decipher, much as one reads tea leaves, just what Robinson is planning.

Much, for instance, was made of Robinson's recent purchase of Newman's acreage because it included land that stretched out to within a few hundred yards of the railroad that bisects the Shore from north to south. An interview with Newman, however, reveals that Robinson didn't want the land at all and only bought it because Newman insisted that Robinson buy all his holdings in a package. Actually, Newman says, it was his land close to Oyster that Robinson wanted.

For his part, Bull doubts that the purchases have anything to do with an oil-related project. "There's not enough fresh water here to handle something that industrial," he says. "It couldn't support refining."

Today, there has been only one hint as to Robinson's intent. That occurred in March 1981 when his Norfolk attorney, T. H. Willcox, wrote a letter to the county asking that it grant Robinson's properties its most intense residential zoning.

In that letter, Willcox wrote that Robinson "expected to hold these properties for appreciation until such time as economic conditions warranted their development for other purposes."

In the end, no action was ever taken on the zoning request, according to Bull, who claims that the request says little about Robinson's ultimate plans for the land. "If he had that zoning, he could down-zone easily to anything he wants," Bull says. "It the rezoning just gives him flexibility, that's all."

Bull and others speculate that Robinson may simply be acting in behalf of one of his clients who wishes to remain anonymous. The list of Reed, Smith clients is an impressive one, including the likes of The Mellon Bank, Westinghouse, U.S. Steel, Quaker State Oil, Nabisco, Rockwell International, Gulf Oil, and the Great Atlantic and Pacific Tea Co., among many others.

According to knowledgeable sources, Robinson is a mid-level attorney in the firm, a graduate of Princeton University with a law degree from the University of Pennsylvania.

One of the few indications of possible intent is the fact that Robinson has given most of those whose land he bought 3- to 5-year leases on their properities, in some cases totally rent and tax free. In one case, he gave a former owner a five-year lease plus another five-year option, indicating that Robinson's development plans could be anywhere from 5 to 10 years away.

The Shore, oldtimers say, is notorious for big land deals that collapse, such as a plan for large vacation community and proposed construction of an oil rig assembly plant. All failed in the 1970s. So, most of those who sold recently say they have been delighted at the chance to get rid of properties, particularly at a time when real estate has been unsaleable.

"It's the only little pocket on the Eastern Shore of Virginia where anything is moving at all," says Broun Dameron, who bought a house in Oyster as a vacation home in 1980 for $15,000 only to give in to an offer of $35,000 by Robinson 14 months later.

There are, however, one or two land owners who vow never to sell. "He asked me to name my price," says Ruby Crumb, who was offered $10,000 for her one acre on the north side of the Oyster inlet that she bought five years ago for $1,800. "So I said 'No.' He came back four or five months later but I still said 'no.'

"No way I'm ever gonna change my mind," she says. "This is the only piece of land I ever owned in all my life, and nobody's gonna take it from me." CAPTION: Picture 1, A general view of the harbor in the fishing village of Oyster, Va., left, shows how the village got its name as oyster shells pile up on the shore.; Picture 2, At right is a picture of the village's post office. A Pennsylvanian man has spent $3.3 million buying property in Oyster. By Douglas Chevalier -- The Washington Post; Map, no caption, The Washington Post