When FBI agents said they had arrested a retired Navy man as a Soviet spy, news wires flashed across the nation a two-year-old photo of a bearded, sharp-eyed man posing with electronic devices that he said were the tools of his trade as a private detective.

Today, that photo could be swapped for an album of hazy, contradictory and baffling pictures -- glimpses others now offer of John Anthony Walker Jr., a private eye with a penchant for disguises, who spoke as an unwavering patriot to his friends but whom investigators charge with handing over national secrets of the most sensitive sort.

To the nuns of St. Paul's High School in Scranton, Pa., Johnny Walker was the quiet, thin, good-looking boy who spent his nights ushering at the local movie theater and left school one year shy of graduation to help his family through hard times.

To the partner in his private detective agency in Virginia Beach, he was a fun-loving ex-sailor who used to brag about his top secret clearance and investigative skills, kept a color photo of President Reagan on his desk and espoused conservative views.

To his 50-year-old brother, Arthur, who was arrested last week on espionage charges, he was the flamboyant younger brother who followed him into the Navy, kept in close contact and drew him into his detective firm and other business ventures.

To his son, Michael, the youngest of Walker's four children and a Navy seaman also charged in the alleged espionage scheme, Johnny Walker was the father he revered, who, he once told friends, was a spy for the United States.

And to federal agents who have been tracking John Walker's movements for six months, he is the linchpin of a greed-driven conspiracy of fellow Navy men to funnel defense secrets to the Soviets, a traitor whose Norfolk house contained a cache of classified documents and arcane tools of the espionage trade.

Johnny Walker "had a theory about being a private investigator," said one of his former employes, Lonzo Thompson of Norfolk. "His theory was: Always set the person up. Just don't sit there. Tempt them. Play on a person's greed. He felt everybody was basically greedy and you always get them through their greed."

Walker was arrested in the early hours of May 20, after he made a nighttime trip to a rural area of Montgomery County. There, FBI agents said, Walker, 47, left a paper shopping bag partly stuffed with trash behind a telephone pole in Poolesville.

Agents who had been following Walker for six months found 75 classified Navy documents in the bag, according to law enforcement officials.

At the time of his arrest, Walker, a former chief warrant officer and communications specialist, was carrying an envelope containing detailed instructions from the Soviets on how to leave and remove information at planned drop sites and maps of drop sites in the Washington area, agents said.

Two days later, his son Michael, a 22-year-old sailor aboard the nuclear aircraft carrier USS Nimitz, was charged with espionage and with aiding and abetting the commission of espionage. Agents said a box full of classified documents was stowed near his bunk at the time of his arrest. Later, they filed court documents that revealed correspondence between the father and son referring to previous deliveries and problems with storing the "souvenirs."

Last week, John Walker's brother Arthur, a retired Navy lieutenant commander, was arrested on charges that, beginning in 1980, he gave his brother confidential documents from the Chesapeake, Va., defense contracting firm where he worked as an engineer. Affidavits filed in U.S. District Court in Norfolk said Arthur admitted his role to the FBI.

Other arrests will follow, according to FBI Assistant Director Bill Baker. An agent testified that John Walker may have been spying against his country for as long as 18 years, a period that makes the case, both in size and in seriousness, a bigger threat to national security than the FBI had expected.

If John Walker acted as federal authorities allege, what drew him into a life style of secret drop-offs, secluded meetings and coded messages, and how did he avoid detection for so long? How were other family members allegedly drawn in? What prompted his former wife, Barbara Joy Crowley Walker, to turn him in nine years after their divorce? All those are elusive pieces of a puzzle that agents admit they are still struggling to solve.

"I'm afraid to pick up the paper and see who's in trouble next," said his younger brother James, 45, who lives in Scranton with their 73-year-old mother, Margaret. "My mother's not answering the phone. She refuses to read anything about her sons." Instead, he said, she spends her days praying.

Federal agents said financial gain was the motivating factor, although FBI searches have not uncovered large sums in secret bank accounts or elsewhere. The largest alleged payment disclosed is the $35,000 that the FBI said a confidential source reported seeing Walker pick up 15 years ago.

But associates and family members dispute the FBI claim that money made him do it.

"If he indeed is guilty of the charges, I don't think it was for financial reasons. A lot of John was an act, was a front," said Laurie Robinson, part-owner with Walker of Confidential Reports Inc., the private detective firm. "He probably got into something he couldn't get out of . . . . He's the kind of person who likes to get into intriguing, mysterious-type situations."

Walker, the middle of three sons, entered the Navy in October 1955 by enlisting in Scranton, where his father, John Sr., managed the local movie theater and later became a news broadcaster for radio station WEJO.

In Scranton, Walker attended two academically challenging Catholic high schools, according to church records. At night, he was an usher at the Roosevelt movie theater, run by his father, a sometime summer stock actor.

James Walker described his older brother as a young boy who was "gung-ho" about mystery. "He liked detective things, reading stories about detectives. It was maybe one of his dreams."

Young John never graduated from high school, leaving to run a paper route and help out with a "family problem," teachers and associates said. In 1960, his father deserted the family, according to court records. In 1964, the divorce became final.

" Johnny Walker was plenty bright enough but he was an underachiever," said a retired nun who taught science classes that he attended in his last year at St. Paul's High School. "He was suffering from a bad home condition but he didn't let that be an obvious item in his life with us . . . . He was a good-looking kid with a certain manliness about him."

Eighteen months after joining the Navy, he married Barbara Joy Crowley in Durham, N.C. The couple, both Catholics and both in their teens, had four children in the next six years: Margaret Ann, Laura Mae, Cynthia Marie and Michael Lance.

From 1957 to 1976, the family moved from Virginia to California and back, following Walker's naval career from ship to submarine to shore duty, while he gained clearance to see top secret information with special access to codes and communication information.

It was sometime in 1968 that Walker began working for the Soviet Union, according to two confidential sources quoted in an FBI affidavit.

As Walker's career advanced, his family life dissolved. In June 1976, he and his wife Barbara were divorced, citing irreconcilable differences.

" Barbara Walker was always suspicious of extra-marital affairs," said Laurie Robinson, who said she saw the woman "storm" into the investigation firm's office several times to angrily confront her husband. Near the end of the marriage, Walker told Robinson he would walk in the door and his wife would start complaining. Walker would immediately turn around and say: 'I'm leaving. Goodbye,' " Robinson said he told her.

A month after the divorce, Walker, who had received two Navy commendation medals, a good conduct medal, the National Defense Service Medal and the Vietnam Service Medal in his 21-year career, retired from the service.

Barbara Walker and the children moved to Skowhegan, Maine, where she worked cementing shoes in a factory until about a year ago, associates said. Then she moved to West Dennis, Mass., where she began working in a gift store just down the street from the apartment where she and her daughter, Cynthia, live.

Coworkers of Barbara Walker describe her as "hard working and friendly." A widow who sometimes drove Walker to work and shared a cup of coffee with her said she has a sharp wit and often jokes about daily problems in her life, and often spoke of her children.

"I would be very much surprised if she knew that Michael had been involved in this spy thing. I know he sent her a Mother's Day gift."

After living with his mother for a short time in Maine, Michael returned to his father. Quieter, more polite, and with noticeably shorter hair, neighbors said, the young boy looked to his father for approval and, in the words of one, would "do damn near anything to please him."

Indeed, FBI officials said Michael Walker's alleged espionage activities may have been motivated in part by his admiration for his father. "With the son, you might have more of a father-figure kind of thing," said FBI assistant director Baker.

After the divorce, neighbors and associates said the father and son appeared to enjoy a close relationship in their home, which a friend said was decorated "like a bachelor pad," with one old sofa in the living room and pictures of submarines on the wall.

They shared what possessions the father had collected over the years: a 1968 houseboat, a 1977 airplane, a 1981 Chrysler and a 1968 Oldsmobile. Land holdings in South Carolina and North Carolina were properties that family members, including James in Scranton, knew about but never questioned how they were acquired.

"He Michael Walker told me once his dad was a spy, but he said a spy for the U.S.," said a young man who described himself as one of Michael Walker's best friends during his senior year at Ryan Upper High School in Norfolk. Michael Walker made the remark after his friend noticed the plane and the boat that Walker owned. The friend, who still lives in Norfolk, said he did not want to reveal his name because he did not want to be contacted by authorities.

Father and son at times discussed Michael's future. Walker talked his son into joining the Navy in December 1982, Robinson remembered. "John said the pay was low but the benefits made it worthwhile," she said.

During the years just after his divorce, John Walker began setting himself up in business as a private investigator. He started a car radio business with his brother Arthur and began taking electronics courses. Later, he worked for Wackenhut Corp., an international security firm.

In 1980, he bought Confidential Reports Inc., and began building it into a company that his partner said now grosses $120,000 a year. He founded two other intelligence firms, Electronic Counter-spy and Associated Agents, firms that Robinson said were limited to de-bugging tasks. Among the companies for which Walker did such work is Newport News Shipbuilding and Dry Dock Co., a major defense contractor.

Walker's brother Arthur, whose full-time job was with the defense contracting firm of VSE in Chesapeake, Va., is listed as a corporate officer with at least one of Walker's firms, and worked about 10 hours a month as an investigator, according to Robinson.

As time went by, John Walker, the boyhood usher who used to watch movie after movie in his father's theater, began fancying himself as a master of disguise and an actor destined to deceive, friends and associates say.

Walker struck Ted Ulrich, who worked with him at Wackenhut and Confidential Reports, as "a frustrated movie actor" who loved the fantasy of role-playing -- "being a millionaire one day, a bum the next."

Walker's enthusiasm for his job -- associates and coworkers described him as an extremely good and dedicated investigator -- sometimes backfired. He was sued by a Virginia Beach woman who accused him of trespassing on her property in a variety of disguises while trying to collect information.

According to the suit, which is unresolved, Walker appeared as a "Boy Scout leader looking for a campsite, a surveyor purporting to survey the land in the vicinity, a birdwatcher attempting to take pictures or photographs of wildlife and also as a Catholic priest."

In 1982, as Walker's businesses prospered, he began a steady relationship with a woman he met during a business meeting. Pamela K. Carroll, now a police officer in Norfolk, worked for one year for Walker, her attorney James McKenry said. The relationship lasted until Walker was arrested May 20.

"She had no earthly idea about alleged spy activities ," said McKenry. He said Carroll received only two gifts from Walker in their three-year relationship, a gold ring and another piece of jewelry.

Walker portrayed himself as an unabashed patriot and a political conservative, friends said. He kept an official White House photo of Reagan, in a denim jacket, on his desk. He told his coworkers he "despised the Democrats and loved what Reagan had done for the U.S. and loved that he allowed more money than any other president for defense," Robinson said.

He also may have been a member of the Ku Klux Klan. The Anti-Defamation League of B'nai B'rith said information in its files indicated that Walker may have been the Virginia state organizer for the Invisible Empire Knights of the Ku Klux Klan. The Klan's Imperial Wizard Jim Blair denied any link.

"Obviously, if the spy charges are true, there is a whole side of him that I had no knowledge of," said Laurie Robinson. "How he could conceal it so well -- when we spent 80 to 90 percent of our time together -- just flabbergasts me."

The move that was to change Walker's life came early this year or late last year. Walker's ex-wife Barbara asked Chester Buck, her Cape Cod landlord, to arrange a meeting with the FBI.

"She didn't reveal anything to me and I didn't ask her," Buck said. "She just said she had something she wanted to talk to the FBI about."

Walker would not talk about the trip or her involvement with the case. Buck, a high school guidance counselor, said he called FBI agent Walter Price in Hyannis and asked him to get in touch with Barbara Walker.

Although the FBI has said it will reveal the identities of its confidential sources only when -- and if -- the Walkers stand trial, sources have said that Walker was turned in by his ex-wife and one of their daughters. The FBI's Baker said in an interview last week that agents had no clue to Walker's alleged spy activities until a "walk-in" confidential informant came forward about six months ago.

The FBI surveillance, supervised by special agent Joseph R. Wolfinger, included among other techniques wiretaps of Walker's car, boat and business telephones authorized by the Foreign Intelligence Surveillance Court, a super-secret espionage court located in Washington.

In mid-May, agents got the break they had been waiting for. Here is what happened next, according to affidavits and testimony:

Agents who had been monitoring the wiretaps "overheard Walker discussing with several people that he had something scheduled" the weekend of May 18 and 19 "that only he could do," one affidavit states.

Walker told people, unnamed in the affidavit, that he was heading to Charlotte, N.C., and planned to return to Norfolk on Monday, May 20.

Shortly after noon Sunday, agents saw Walker get into his van. But instead of driving south toward Charlotte, he headed north.

When Walker reached the Potomac area several hours later, he spent an hour making U-turns, intermittently stopping at the roadside, and driving in circles "in a manner calculated to detect if he was being followed," the affidavit states.

The FBI lost Walker for nearly three hours. Then, agents stationed near Boswell Lane, north of Potomac, spotted him. Walker spent another 40 minutes "stopping, starting, getting out of his vehicle, and making U-turns in an effort to detect surveillance," according to the affidavit.

At 8:37 p.m., FBI agents saw Walker at Partnership Road in Poolesville, standing by a tree posted with a "No Hunting" sign.

An hour later, Special Agent Bruce K. Brahe retrieved from the site a brown paper shopping bag that would lead to Walker's arrest. Inside was a Manila envelope sealed with masking tape. Inside that was a white plastic bag also sealed with tape, containing, according to prosecutors, documents from the USS Nimitz.

Agents also spotted Soviet Vice Consul Aleksey Gavrilovich Tkachenko nearby and waited for him to make a move. But Tkachenko did not pick up either the bag that Walker dropped or another bag filled with blank papers wrapped in the same way that the FBI had left as a "dummy," sources said.

Tkachenko left the country four days later. FBI counterintelligence experts said they believe he was recalled to Moscow to explain what went awry.

Several hours after the alleged drop, Walker was still driving around the Montgomery County countryside. At 11:04 p.m. and then at 11:28 he returned to the "drop site," agents say.

Shortly after midnight, he left and drove to a Ramada Inn in Rockville, where he was registered in Room 763 under the name of J.A. Johnson. About four hours later, in the hallway of the motel, FBI agents arrested Walker, who allegedly pulled a revolver on them.

The FBI's search of the plastic bag retrieved at the drop site gave agents what appears to be the first indication that others, including Walker relatives, could be involved.

Included in the material was a three-page, computer-printed letter addressed, "Dear Friend." It advised: "This delivery consists of material from 'S' and is similar to the previously supplied material." The note also mentions a "K," described as being "involved in carrier and amphibious ship maintenance planning."

Two other letters, addressed "Dear Johnny," were from "D."

Thee FBI concluded that "S" was Walker's son Michael, assigned to the USS Nimitz. He was arrested on board the Nimitz May 22 and was indicted with his father Tuesday on espionage and conspiracy charges.

"K," agents decided, was John's brother Arthur, whose duties at VSE Corp. involved carrier and amphibious ship maintenance planning. Arthur Walker was arrested Wednesday and is to appear before a federal magistrate tomorrow.

And "D" -- not yet arrested -- is believed to be a retired Navy enlisted man living on the West Coast, where agents have been questioning associates of John Walker.

FBI Assistant Director Baker said Friday that agents are scouring "all aspects of John Walker's life" to determine who else might be involved. And the Navy Thursday announced it has appointed a panel of experts, headed by Chief of Naval Intelligence Rear Adm. John Butts, to review the Walkers' assignments and access to classified information "to determine the possibile scope of compromise."

Like the Walker family in Scranton and business associates in Norfolk and Virginia Beach, the Navy community is reeling from the news of alleged spies among them.

"Up until now we've been one great big brotherhood of trust and responsibility," Retired Rear Adm. Gene LaRocque said.

This, he said, "just makes me sick to my stomach."