Robert Lockhard is probably the only federal supervisor who requires trainees to spend time in elementary school classes, watching children learn penmanship.

"When you're writing, you pretty well depend on a habit you've developed with your hand," Lockhard said.

Being able to distinguish individual idiosyncracies from the "national" writing habits learned in school is crucial, Lockhard said, to learning how to spot forged documents.

That back-to-basics philosophy, developed in the 26 years since Lockhard examined his first documents for the Eugene, Ore., police department, is the underpinning of the Immigration and Naturalization Service's Office of Forensic Document Examiners.

In its first five years, the office has detected hundreds of faked visas, discovered authentic visas sewn into passports where they don't belong and identified hand-drawn consular-stamp forgeries so finely crafted that only sophisticated machinery can detect them.

Lockhard and his colleagues have helped alert American consular officials abroad to the latest techniques in document fraud and have served an important role in the Justice Department's pursuit of suspected Nazi war criminals and Nazi collaborators accused of entering the United States fraudulently.

In fact, three of the office's four professional document examiners spent weeks learning the handwriting styles taught in Eastern Europe and the eastern Soviet Union between 1900 and 1925. Some of the children who learned those styles grew up to be Nazi collaborators.

"In looking at a foreign handwriting, you might see what you thought was a unique 'R,' " examiner Gideon Epstein said. "But that formation of the 'R' was what was taught in the schools there.

"We spent a lot of time getting handwriting samples from individuals of the same nationality and the same age as the suspects, so we could separate the national handwriting characteristics from the individual ones."

Yet, it is difficult for Epstein, Lockhard and their colleague, Bill McCarthy, to work with documents written in Cyrillic, the script used in the Soviet Union, the Baltic countries and parts of Eastern Europe.

But, Epstein said, "if you have other samples in Cyrillic to look at and you identify something that's a unique characteristic, it just becomes a comparison of shapes and forms: the size of loops, the space of loops, the initial strokes, the ending strokes. It really doesn't require a knowledge of the language or the alphabet."

In most of the Nazi-collaborator cases, Epstein and McCarthy had to work in a small room provided by the Soviet Embassy, whose officials were willing to bring the crucial documentary evidence to the United States but not to turn it over to federal authorities.

In 1982, Epstein was able to identify the handwriting of Valerian Trifa, who headed the 35,000-member Romanian Orthodox Episcopate in America until his deportation last year.

The Justice Department contended that Trifa had "enjoyed political refuge" provided by the Nazis, citing postcards and letters that he was thought to have written. The letters contradicted Trifa's story that he had been a Nazi prisoner who had worked at forced labor. Epstein's analysis showed that the bishop had written them.

Those are the cases the examiners remember. But Lockhard's first INS case was perhaps more typical: In 1979 he identified as a forgery a customs declaration that a Nigerian had presented to inspectors at Dulles airport.

"The thing I tell people who ask about us is this," said Lockhard, 55. "The INS inspectors at the borders are like physicians, doctors of documents. The examine documents day after day the way doctors examine patients.

"We are the pathologists."

He and his colleagues have the machinery of their trade: a device that compares the inks on different documents to detect forgeries of federal seals or stamps, ultraviolet and infrared scanning devices that allow them to look through erasures, split-screen devices for comparing suspect documents with authentic ones and magnifying devices.

They also have acquired the passports of nearly every country.

With the help of these devices, they come to know the work of the foreign counterfeiting operations that are their main adversaries. Lockhard says that by preparing a slide show on the types of forgeries prevalent among illegal Haitian immigrants and presenting the show to Foreign Service and airline personnel in Port au Prince, Haiti, his office was able to cut the number of Haitians trying to depart for the United States with illegal documents from 80 a month to two a month since October.

"But," Lockhard said, "you can never stop all the fraud . . . . They'll use one particular method till they're detected, then they'll stop and use another. Then a few years later they'll dust off the first and use it again.