Developer Frederick Ramsay, who disappeared from Fairfax County nearly two years ago and left behind an unfinished town house development and about $2 million in debts, has been jailed in North Carolina after pleading guilty to extortion, theft and money laundering that occurred there and in Northern Virginia, federal authorities said this week.

Ramsay, owner of Leesburg Real Estate Development Co. when he vanished, is serving a 3 1/2-year sentence. He pleaded guilty last month to Fairfax County offenses of fraud and money laundering and to charges of extortion and theft involving two Charlotte, N.C., banks.

Half of the 28 houses in the Villages of Occoquan, at the intersection of Hooes and Silver Brook roads in southern Fairfax, had been finished and sold when Ramsay disappeared in November 1988. But some of the prospective buyers who had signed contracts to purchase the other 14 houses lost money they gave Ramsay to pay for extra and upgraded features, two of the buyers said.

After Ramsay obtained a $2.1 million construction loan from Potomac Savings Bank in Silver Spring in June 1987, he used some of the money to buy land in Lorton for the development but he used "several hundred thousand dollars for his own purposes," according to a statement he signed when pleading guilty to the charges brought against him by Assistant U.S. Attorney Constance H. Frogale in Alexandria.

When he vanished, Ramsay also owed $200,000 to Community Bank and Trust of Virginia in Sterling, money he withdrew from a line of credit, plus more than $42,000 in interest, the statement said.

In North Carolina, the developer pleaded guilty to stealing more than $100 each from First Union National Bank and Citizens National Bank, both in Charlotte, according to court documents.

Ramsay was arrested in June after he telephoned the North Carolina banks and threatened to set off bombs unless he was given money, according to a spokesman for the U.S. attorney's office for the Western District of North Carolina. The developer picked up the cash that the banks, following his instructions, left for him, but was arrested a few blocks away, according to the spokesman.

When he applied for the line of credit from Community Bank and Trust in November 1988, Ramsay told bank President James Newsome he needed the money to speed up completion of the Villages of Occoquan town houses, according to Ramsay's court statement.

As proof of his creditworthiness, Ramsay gave the bank fake federal tax returns and pledged sales agreements to 18 houses as collateral, although such a pledge violated his agreement with Potomac Savings Bank, according to the statement he signed.

He withdraw the $200,000 from his line of credit in two amounts, on Nov. 22 and Nov. 28, 1988, according to his statement. On the 28th he also cashed four checks for $9,000 each on his company's account with Sovran Bank. He cashed the checks at four different Sovran branches in Northern Virginia, violating federal money laundering laws requiring that currency transactions of more than $10,000 be reported to the Internal Revenue Service, Ramsay acknowledged in his statement.

On Nov. 29, Ramsay "absconded" without finishing the Lorton development, without paying many of the vendors and workers or the money owed on his line of credit, the court documents said.

Thorn McDaniel, chief of the Internal Revenue Service's criminal investigation division in Richmond, said many people believe they can avoid making the reports of currency transactions by cashing multiple checks or making multiple cash payments of just under $10,000. But the law applies to such transactions if they are made for a related purpose, he said.

Officials of Potomac Savings Bank and owners of the 14 homes sold by Ramsay soon discovered that the developer had forged signatures on waivers of mechanic's liens to get "several thousand dollars {from the bank} which he used for his own purposes," the court statement said.

A mechanic's lien asks a court to order sale of a property to pay a debt, leaving the homeowner the choice of paying the bill or losing his house. The owner can then sue the builder who incurred the debt, but a mechanic's lien is usually filed because the builder cannot or will not pay.

Ramsay owed more than $1 million to a dozen subcontractors, spokesmen for the companies said at the time.

Nelson Blitz, attorney for Potomac Kitchens, which supplied the kitchens at the development, said this week that his client has been paid by homeowners for about half the money the company was owed. The bills amounted to about $4,000 per house, he said.

Five of Potomac Kitchens's suits are still pending against homeowners, according to the owners' lawyer, Robert J. Beagan. The mechanics' liens filed on the houses by other subcontractors have been released because of "technical problems with the liens" or, in one case, settled at a cost of $150 per homeowner.

A new developer is working to complete the 14 houses Ramsay left unfinished, and Villages of Occoquan is "a regular community now," said John Cummings, president of the homeowners association.

Most of the prospective purchasers of the 14 unfinished houses were reimbursed for their basic deposits, which were held by a real estate sales company. But most lost money they gave Ramsay for extra features in the homes. Some have since bought other homes, but at higher prices than they expected to pay at Villages of Occoquan.

Tami O'Hara, a Fairfax County government employee, said she and her husband got back their $3,000 deposit but not the estimated $8,000 they paid Ramsay for upgraded and optional features in the house. The couple has since bought another house in Manassas for $160,000, about $10,000 more than they expected to pay for the Villages of Occoquan home.