Friends and relatives call Samuel Loring Morison a workaholic, an oddball genius, an eccentric patrician, a loner in the tightly closed fraternity of U.S. Naval Intelligence operations. As one colleague put it, he was "a cross between an absent-minded professor and a hyper professional."

"In a world where most people wear a tie and coat," the colleague said, "Sam comes in rumpled slacks with his shirttail hanging out."

Despite a long history of family ties to the U.S. defense community, Morison was arrested early this month under the U.S. espionage statute and was released on bail only last week. He declined to talk to reporters. But through court records and interviews with family members, neighbors and the few colleagues willing to discuss the case, a rough picture of Samuel Morison has emerged.

In a squat, windowless building known as NIC-2 at the federal government complex in Suitland, Morison, 39, labored for 10 years with 500 to 600 fellow scientists, analysts and researchers, studying and evaluating Soviet ships and naval weapons systems for the U.S. Naval Intelligence Support Center (NISC).

When he wasn't there, he retreated to his bachelor apartment in nearby Anne Arundel County where, neighbors and a building manager say, he lived with his pet cat, kept to himself, paid his rent on time and immersed himself in books.

Then early on the night of Oct. 1, as Morison was about to board a flight to England at Washington Dulles International Airport, FBI agents stepped from the crowd and arrested him, charging him with leaking classified satellite photographs of Soviet shipbilding operations to a private British military magazine. The pictures, published in the Aug. 11 issue of the London-based Jane's Defence Weekly, showed a state-of-the-art Soviet nuclear-powered aircraft carrier under construction at a shipyard on the Black Sea.

Agents went to Morison's apartment, where they seized several hundred government documents, many of them classified, they claim, as well as a collection of naval photographs Morison had assembled over the years.

Family members and colleagues were stunned at reports of his arrest. A descendant of a prominent Boston family and grandson of the U.S. Navy's foremost historian, the late Samuel Eliot Morison, he seemed an unlikely object of criminal prosecution.

Also, according to colleagues and Pentagon sources, NISC officials knew that Morison moonlighted as a $5,000-a-year part-time editor for Jane's and in fact had their blessing. In the byzantine world of military intelligence with its elaborate gamesmanship of "disinformation" and planted leaks, as well as its own bureaucratic intrigues, colleagues say they are puzzled by what the Morison case may really mean.

Morison was for 22 days after his arrest, then released after his mother, Judith Day Morison of New York, posted a $100,000 bond. Officially on leave without pay from his NISC job, he returned to his apartment in Crofton, a bedroom community in western Anne Arundel County.

Born on Oct. 30, 1944, in London, where his father was serving the American military in World War II, Morison spent much of his youth in New York and Maine. He attended the noted Tabor Academy college preparatory school in Massachusetts and graduated from the University of Louisville in 1967.

He served as an officer and later a civilian in the Navy, seeing action off the coast of Vietnam in 1968. He joined NISC in 1974 and worked his way up to the $30,000-a-year position he held at the time of his arrest as a Soviet amphibious ship analyst with a top-secret clearance.

He knows his stuff, say family members and colleagues, and he is respected for his analytical skills and precisely written reports. Owlish and graying at the temples, he walks with an awkward gait, and his rapid British-tinged speech is sometimes encumbered with what appears to be a stutter.

According to court papers filed by his attorneys, Morison suffers from epilepsy and a chronic thyroid condition, requiring daily medication. While he was jailed after his Oct. 1 arrest, guards temporarily lost his medication, causing him to undergo severe stress and an "epileptic episode," according to the court papers. "It was a gruesome experience for him," said defense attorney Armistead P. Rood.

During a bail hearing, federal prosecutors suggested that Morison was fed up with his work at NISC and was going to England to seek permanent employment with Jane's and therefore should be held on at least $250,000 bond to discourage his flight.

Defense attorneys countered that he was going for a short vacation. As evidence, they said he had a round-trip ticket and had arranged to board his pet cat for one week.

Further, they said, Morison was traveling with a girlfriend, identified as Sylvia J. Griffiths. She and a second woman, identified as Louise Anne McKrill, were with Morison at the airport when he was arrested. Both were questioned and released by FBI agents.

Throughout their court papers, defense attorneys describe Morison as patriotic and loyal to America. "Probably the most influential figure in Mr. Morison's youth and later career," the papers said, "was his paternal grandfather, Rear Adm. Samuel Eliot Morison, the distinguished Harvard professor who became the preeminent American Naval historian of this century." The attorneys said Morison is currently editing his grandfather's wartime diaries for publication.

While not acknowledging that Morison disclosed classified photographs, the attorneys say that such unauthorized disclosures occur routinely but are rarely prosecuted, mainly because there is "no explicit statutory prohibition." They likened the Morison case to the so-called "Pentagon Papers" case in which former Defense Department official Daniel Ellsberg and Rand Corp. analyst Anthony Russo were charged with leaking classified documents on the Vietnam War to the New York Times in 1971. The prosecution was dropped in midtrial after the judge ruled there was governmental misconduct in the investigation of the case. There have been no similar prosecutions since then.