FBI agents searching the two-story brick-and-frame home of accused spy John Anthony Walker Jr. within hours of his arrest Monday found two letters from his sailor son that, in turn, led to a search on Tuesday of the son's personal effects aboard the nuclear aircraft carrier USS Nimitz. Next to his bunk, searchers found a 15-pound box of classified documents, officials said.

Today, Seaman Michael Lance Walker, 22, also was charged with espionage and with aiding and abetting the commission of espionage. The younger Walker was being held in the brig of the ship, which is anchored in the Israeli port of Haifa. Meanwhile, here in this Navy-minded city that both father and son called home, investigators were trying along with friends and neighbors to comprehend the many sides of the retired career enlisted officer.

He piloted his own airplane, sometimes disguised himself as a priest and once had a neighbor help him make a peephole in the trunk of an old car to improve his picture-taking surveillance tactics.

For Walker Jr., 47, a former Navy communications specialist who built a second career as a private detective in this picturesque seaside community of ships, harbors and neatly pressed Navy uniforms, it was all part of the cloak-and-dagger life that he loved.

"It's damn glamorous work," Walker told a writer for an article that appeared in the September 1983 issue of Commonwealth magazine.

But there was a bizarre and not-so-glamorous twist to the Johnny Walker story this week when he was arrested by FBI agents in a Rockville motel and charged with passing secrets to the Soviet Union. The arrest was made at about 3:30 a.m. Monday after Walker allegedly left a paper shopping bag containing 129 classified Navy documents at a drop site near Poolesville in western Montgomery County. Some of the documents were believed to have come from the Nimitz, the FBI said.

Walker is being held without bond in the Baltimore jail, pending a May 29 hearing in federal court. Officials said they believed the alleged espionage operation had been under way for at least 18 years and covered at least some of the time that Walker served in the Navy.

At retirement in 1976, Walker held a security clearance of "Top Secret Crypto," entitling him to see top secret information with special access to codes and communication information, the FBI said.

From interviews with neighbors and others who knew Walker, he emerges as a complicated man with not one but many lives:

* He was a member in good standing of the Better Business Bureau of Southeast Virginia and he served as an unpaid volunteer member of the bureau's consumer arbitration program, according to James E. Bryan, the bureau's executive vice president.

* He was a defendant in a million-dollar lawsuit filed by a Virginia Beach woman who accused him of coming onto her property in 1980 in a series of disguises to collect information. The suit said he came 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." A jury trial has been set for Sept. 10, court records show.

* He contributed his time to helping locate missing children and his work was recognized last year by Norfolk Channel 13 (WVEC-TV).

* He was the father of four children, three girls and a boy, Michael, who lived in a two-story home in a middle-income neighborhood here. His marriage broke up a few years ago, neighbors said.

* He dated a number of attractive women, neighbors said, and one regular date has been Norfolk policewoman Pamela K. Carroll.

* He loved flying his four-seat, single-engine airplane on assignments around the country, doing surveillance work from his houseboat and maintaining a collection of pistols, shotguns, radios and binoculars for use by his staff of investigators, according to the Commonwealth magazine story. Walker also had four suitcases filled with what the magazine feature writer described as "an array of digital dials, miniscreens and wires."

* He is described by his partner, Laurie Robinson, as a warm, intense, fun-loving man who would do anything for his friends and who liked to play practical jokes. "He would come into the office and pull out a dart gun -- the kind that shoots the darts with suction cups and shoot it past us at the wall."

Robinson, 29, said she went into the detective business with Walker four years ago when they founded three companies: Confidential Reports Inc., Electronic Debugging, and Associated Agents Inc.

Yesterday, Robinson stood outside the office on the second floor of a small brick bulding in Virginia Beach and shook her head in disbelief.

"The reason I am so shocked is that we spent so much time together, working out of state, out of country, working on the houseboat, flying around in the airplane . . . so this has taken me by tremendous surprise," she said.

Robinson said she plans to reopen Confidential Reports for business today. The firm employs about 40 people and has clients depending on its services, she said. Robinson said she was uncertain what the future holds for Electronic Debugging Inc., and Associated Agents, the two companies operated by Walker and housed in the same offices.

Walker was born July 28, 1937, in the District of Columbia and inducted into the Navy Oct. 25, 1955, in Scranton, Pa., according to Navy records. The Navy said that he received during his 21-year career two Navy commendation medals, a good conduct medal, the National Defense Service Medal and the Vietnam Service Medal. He attended submarine school and served aboard two submarines and several ships, the Navy said.

Walker had been serving in Norfolk as a chief warrant officer for two years before his retirement July 31, 1976, the Navy said.

Walker's father, John A. Walker Sr., 72, told the Virginian-Pilot in a front page story published yesterday that he is "terribly distressed" about what has happened to his son. "I never thought I would have a son who was a traitor," he said. "I don't want to be associated with a traitor to my country."

The Navy said that Michael Walker entered the Navy Dec. 13, 1982, after graduating from Ryan Upper High School in Norfolk in June 1982. After boot camp, Walker was assigned to Fighter Squadron 102 at the naval air station at Oceana, Va. From there he was assigned to the USS Nimitz on Jan. 31, 1984. Since July 1984, Walker has worked in the operations department administrative offices on the Nimitz. The Navy said he is married.

A March 6 letter from the son to the father that was seized in the search of the Walker residence and cited in a government affidavit read in part:

"Jaws, enclosed is a copy of my latest evaluation, not bad is it . . . . If they only knew how much I hate this carrier . . . . I have a lot of miscellaneous bullshit, I am just a little worried about the quantity. Storing it is becoming a problem."

Another letter dated April 23, also cited in the affidavit, said, "Jaws, I asked you in my previous letter what I should do about the increasing amounts of photos I have been acquiring. Do you have any suggestions? At the rate I am going I will have over a hundred pounds of sovenirs sic . . . . Currently, I have two boxes that weigh about 15 pounds each."

Michael Walker is remembered by the people in the neighborhood as a pleasant, courteous teen-ager with short hair who sometimes volunteered to mow the lawns of neighbors without charging them.

Dorothy Gandy, who lives next door to the Walker home, said that she remembers Michael Walker coming over one day to talk to her mother as her mother worked in the yard with the flowers.

"He talked to her about the flowers. He was very interested in the names," Gandy said. Since his son left home about two years ago, John Walker has lived alone. Neighbors said he liked to sit on the deck at the rear of the house and have cookouts or drinks in the evening, usually with a girlfriend. Gandy said Walker's presence in the neighborhood always made her feel safe when her husband, Don, a retired Navy man, was away at sea.

Don Gandy, who wears boots and has a long white beard, said Walker recruited him once to help enlarge a hole in the trunk of an old car that Walker used in his detective work. "He wanted the hole bigger so he could take pictures through it when he was on a job," Gandy said.

Neighbors say they last saw Walker Saturday morning. "He was loading up his new van with suitcases," Gandy said. "We didn't pay any attention because he's always loading and unloading his van and going somewhere."