Federal investigators have forced evidence of pervasive corruption in 27 of the 30 Generakl Services Administration supply stores that provide office supplies for federal workers in Washington and the surrounding region, according to sources close to the investigation.

The evidence shows, according to the sources, that managers or assistant managers of the GSA stores received television sets, clothing, vacation trips and cash in return for allowing private firms to be paid by GSA for supplies that were never delivered to the GSA stores.

One investigator has estimated that, as a result of this corruption, the federal government never received as much as half of the $37.6 million worth of office supplies GSA buys each year for distribution to federal workers through the 30 stores.

"The patterns (of corruption) we've uncovered are pervasive to a shocking extent," another source said."The problems is it's so unbelieveable."

The GSA supply stores, located in Washington, Maryland, Virginia, Pennsylvania and Delaware, stock thousands of different kinds of office supplies ranging from pencils, paper clips and stationery to briefcases, waste baskets and desk accessories.

Each store resembles a large self-service office supply supermarket where employes from various federal agencies fill shopping carts with supplier from the shelves and pay for them with interagency charge cards.

The investigation of the GSA supply stores began when Internal Revenue Service auditors discovered irregularities in office supplies that were supposed to be going from GSA to an IRS office in Cleveland. GSA investigators later found similar irregularies at a GSA supply store in Baltimore, where the U.S. attorney's office is now directing the extensive investigation of the GSA supply stores throughout this region.

In addition to that investigation, the U.S. attorney's office in Washington and the FBI have found evidence, previously reported, that GSA managers of federal office buildings here have been receiving millions of dollars in payoffs from companies that do maintenance and repair work in their buildings. In return for these alleged bribes, sources say, the building managers have allowled the companies to be paid by GSA for work that was never done in the buildings.

In GSA supply store investigations being supervised by the Baltimore U.S. attorney's office, the FBI. GSA investigators and other federal agents collected evidence that supplies were never being delivered to the stores through a relatively simple technique: the investigators compared the GSA documents certifying that goods had been delivered with the internal records of the companies that were supposed to be supplying the goods.

For 27 stores, according to the sources, the corporate records showed that supplies paid for by GSA had never been shipped. Through other means, according to the sources, the investigators found evidence that employes at all 27 stores had received a variety of valuable gifts and cash from the supply firms involved.

At least 50 GSA employes and office supply companies, most of them here in Washington, are expected to be indicted by a federal grand jury being directed by the U.S. attorney's office in Baltimore, according to sources.

In those cases where a clear pattern of bribery can be documented, the GSA employes and suppliers will be indicted for bribery and defrauding the government, according to the sources. In cases where only the false certification for receipt of supplies that were delivered can be proved, the sources said, the charges will be defrauding the government and making false statements to the government.

Hundreds of other GSA employes who will not be indicted may be disciplined by the agency for lesser offenses, according to sources.

"We can't throw hundreds of cases into our (federal court) system," one source said. "Receiving one color television, for example, may not be big enough to be handled as a federal criminal matter."

Investigator said the corruption apparently was encouraged by lax controls, GSA's emphasis on increasing volume at its supply stores, and a government-wide practice of increasing spending at the end of each fiscal year to justify the next year's budget requests.

Rather than placing emphasis on conserving the taxpayers' money, investigators said, GSA officials encouraged supply store managers to work to increase the volume of supplies they bought and resold to other federal agencies. Until recently, GSA store managers received award certificate if their annual sales exceeded certain levels.

Meanwhile, other government agencies have often gone on spending sprees at the end of each fiscal year because they fear Congress will reduce an agency's appropriations if it has not spent the previous year's budget. GSA supply stores offered these agencies a perfect opportunity to spend their money, investigators said. Purchasing agents for some agencies aranged paper deals with store managers that allowed them to spend the agency's money wihtout actually buying anything.

According to investigators, at the U.S. Army's huge Fort Meade installation in Maryland, Army purchasing agents needed to spend $50,000 by the end of one recent fiscal year but could not possibly use that much in office supplies. Some GSA store managers came to the rescue by allowing the Army purchasing agents to charge $50,000 as having been spent in the supply store while receiving only $20,000 in office supplies.

The excess $30,000 was then allegedly paid by the GSA store managers to office supply companies for goods that were never, delivered to the government. In return, the office supply companies allegedly provided both the store managers and the Army purchasing agents with trips tires, guns, television sets, and cameras, according to an investigator.