The month that her son reported for duty on the USS Nimitz, Barbara Joy Crowley Walker was agonizing over whether to tell authorities she suspected her ex-husband was a Soviet spy, according to a friend of the family who said Walker turned to her for advice.

Shalel Way, 29, whose parents befriended Barbara Walker after she moved to Skowhegan, Maine, in 1976 following her divorce from John A. Walker Jr., said that in January 1984 Barbara Walker asked her for a tarot card reading to help her decide whether to go to the FBI.

"She said she suspected he was giving secrets to the Russians. She said he would get drunk and call her on the phone and brag about it," Way said in an interview at her apartment in Skowhegan, a tiny factory town in central Maine. She said Barbara Walker discussed whether she should contact authorities while sitting in Way's mother's kitchen on a wintry afternoon in January 1984.

As she considered whether to implicate her former husband, Way said, Barbara Walker was apparently unaware of the alleged involvement of her son, Navy Seaman Michael Walker. "She's just about destroyed," said Way, who stated that she overheard part of a telephone conversation between her mother and Barbara Walker after Michael Walker's arrest.

Way said that during that conversation, Barbara Walker told her mother that she doesn't believe her son was really involved and thinks her ex-husband is somehow framing Michael to punish his ex-wife for tipping off the authorities. Barbara Walker's sister-in-law, Pat Crowley, also said Barbara Walker had no clue her actions would lead to her son's arrest.

Walker apparently deliberated for about a year before calling the Hyannis, Mass., office of the FBI about six months ago, providing the tip that triggered the arrests of her ex-husband, a retired chief warrant officer; her son; her former brother-in-law, retired Navy lieutenant commander Arthur James Walker; and a friend and former Navy colleague of John Walker's, retired communications specialist Jerry Alfred Whitworth.

A fifth person, "F," also may be implicated in the alleged espionage ring, according to an FBI affidavit.

Barbara Walker told The Los Angeles Times yesterday that her former husband began spying for the Soviet Union in the late 1960s to get money for a failing South Carolina restaurant in which he had invested. She said he had received "well over $100,000" for his alleged espionage activities.

She said she never would have gone to authorities if she had known it would lead to the arrest of her only son, 22.

"I love Michael so much," she said. "I love my country, but I never could have brought myself to do it if I had known he was part of this thing. I was devastated when I learned Michael was involved."

She said her daughter, Laura Mae Walker Snyder, had told her John Walker tried to enlist her as a spy in 1979 when the daughter was an Army communications specialist at Fort Polk, La.

As for why she finally went to the FBI, Barbara Walker said, "I wanted to protect my children. Was I seeking vengeance? Well, a part of me wanted to see him get what he deserved."

The interview took place in her apartment in West Dennis, Mass. Mrs. Walker, who had worked in a Skowhegan shoe factory after her divorce from Walker in 1976, moved to the Cape Cod community last summer to live with her daughter.

In other developments yesterday: A source familiar with the investigation said the FBI plans today to interview a person at the Naval Air Station in Pensacola, Fla., in connection with the alleged espionage case. Former CIA director Stansfield Turner blamed the lengthy delay in uncovering the alleged espionage ring in part on a reduced emphasis on CIA counterintelligence during the 1970s. The espionage may have begun as long as 20 years ago, according to a federal affidavit.

At a breakfast meeting with reporters, Turner, a retired admiral, said he is alarmed by the possibility that John Walker gave the Soviets "absolutely vital" intelligence about submarine deployment. "What really bothers me," he said, is that such information might accelerate the Soviets' research into methods of locating U.S. submarines below the surface. The Pentagon said that Whitworth was twice reapproved for a "top secret" security clearance during the period in which he is accused of conspiring with John Walker to spy for the Soviet Union. John and Arthur Walker, who both held top secret clearances during their Navy careers, were never subjected to reviews of their security clearances, which are supposed to be conducted every five years, according to a statement from the office of Michael I. Burch, chief Pentagon spokesman. Senate Intelligence Committee Chairman David F. Durenberger (R-Minn.) called on the Reagan administration "to cut in half the amount of information we classify and cut by more than half the number of people who have access to it."

He said security checks for those cleared to see sensitive information were inadequate and that a tendency to classify too much information created a situation in which those with clearances feel "everything can't be that secret so people treat nothing as secret."

Durenberger said in an interview that he believed "we're getting better" at finding spies. At the same time, he said, there is "more spying going on and a lot more clever spying going on." A memorandum filed in federal court in Baltimore said that John Walker, despite a net worth of $174,785 at the time of his arrest May 20, cannot now afford to pay for a lawyer.

Walker's court-appointed lawyers, federal public defenders Fred Warren Bennett and Thomas B. Mason, said in the memorandum that Walker cannot afford to pay the estimated $20,000 to $75,000 costs of his legal defense because the government has placed tax liens against some of Walker's property and seized other assets, including ten 100-ounce bars of silver bullion valued at $6,100.

The Internal Revenue Service yesterday placed liens on Walker's land holdings in North Carolina and South Carolina. It had placed liens Tuesday against his assets in Norfolk. The IRS said he owed $252,487 in back taxes, interest and penalties for the years since 1979.

The IRS often moves to recover back taxes, interest and penalties against those accused of a crime when agents believe a person may not have reported all of his income, legal or illegal.

In the interview yesterday, Way said that Barbara Walker hesitated before going to the FBI because she was uncertain whether John Walker's talk of his escapades as a Soviet spy were true or mere boasting from a man who, friends say, bragged about everything from his detective abilities to his many girlfriends.

"She would say, 'Are you just talking, Johnny, or is this the truth?' " Way said.

Way said Barbara Walker hoped the tarot cards would help illuminate the matter. She said she advised Walker to "be very cautious and make sure you know the whole story, make sure it's not braggadocio."

In a black notebook, Way wrote this account of the afternoon: "Woman holds secret that is of military importance regarding ex-husband John. Will reveal eventually. Caution."

While Way said Barbara Walker was "not a bitter woman at all," friends in Skowhegan said she had little reason to feel kindly toward her ex-husband.

After 19 years of living with her husband in Norfolk on a comfortable income, she had to struggle to make ends meet after their divorce. She had to rent an apartment for $35 a week in a rundown building, they said, before she could afford to move to a nicer two-story house.

She found a job doing piecework at a shoe factory and, according to her sister-in-law Pat Crowley, would work an extra hour in the morning and through her lunch hour to add to her paycheck.

Way, who lives in an apartment behind the house Barbara Walker rented, said she came home in jeans and a sweatshirt covered with soot and glue, too tired to change clothes. "She'd say, 'Johnny Walker did this to me,' " Way said.

Crowley remembered an occasion when Barbara Walker "passed out at work one time, she was so tired. "We kept after her. I said, 'You're working yourself to death and then where will your children be? She'd say, 'Yeah, but I have to pay the fuel bill.' "

Way said that while it appeared from talking to Barbara Walker that her ex-husband "was cruel to her," patriotism was a large part of the reason why Barbara Walker wanted to talk to the FBI.

She said Barbara Walker, who always hung a flag outside on Memorial Day, once told her, "Johnny Walker is a traitor to his country. I'm really going to get him for this. That's my country."

She said Barbara Walker decided to go to authorities once she had the facts, despite fear of reprisals by her ex-husband. "She is a very courageous woman."

Although Barbara Walker's oldest daughter Margaret and son Michael were close to their father and moved back to Norfolk where he lived, friends said her two middle daughters, Cynthia and Laura, seem to share her ill opinion of their father. They complained that he had "mistreated their mother" and favored Michael, Way said. "Michael got all the presents, the money and the trips, and they got nothing."

For his part, John Walker complained that his two middle daughters "only called when they wanted money," according to his business partner, Laurie Robinson.

Michael Walker held a special place in his mother's affections, Way said. Barbara Walker made a trip to attend Michael Walker's graduation from boot camp, according to Crowley.

In a note on one of her tarot reading sessions with Barbara Walker, Way wrote, "Michael, favorite."