Two months before he was arrested as a spy, Robert P. Hanssen dropped in on some old colleagues at the Centre for Counterintelligence and Security Studies in Alexandria.

Inside the center, a school for spooks, Hanssen paused at one of the many photographs displayed on its walls. The staged black-and-white picture depicted a shadowy figure in trench coat and hat, stooping down to pick up a package under a footbridge in a park.

On Feb. 18, FBI agents descended on Hanssen after he dropped his own package of top secret documents in Foxstone Park near his Vienna home. He had stashed it under a footbridge.

"I look back at that now, the way he sort of stopped and stared at that particular picture, and I wonder what he was thinking," recalled Paul D. Moore, a former FBI analyst who teaches at the CI Centre. "I don't think anyone really knows what he was thinking."

Spies are often clear in their motives. CIA analyst Aldrich H. Ames was driven by greed, using the money he received from Moscow to buy a Jaguar and pay cash for a half-million-dollar house. British traitor Kim Philby helped the Soviets out of Marxist fervor. Edward Lee Howard became a turncoat out of spite, after the CIA trained him and then fired him.

But Hanssen is still a riddle. The more information that emerges about his behavior and beliefs, the more contradictory they appear. None of the usual motives for espionage -- greed, ideology or revenge -- seems sufficient to explain the multiple deceptions he engaged in at work, at home and at church. Psychologists and former colleagues are left with more airy theories about Hanssen's relationship with his father or an ego that grew addicted to trying to fool everybody, all the time.

Multiple Secret Lives

The only son of a Chicago cop who had worked as a "Red hunter" during the McCarthy era, Hanssen spouted anticommunist rhetoric at the FBI while selling state secrets to agents of Moscow. He attended church daily and confession weekly, but wrestled in private with a growing obsession with pornography. He lived frugally with his wife, Bonnie, and six children in a heavily mortgaged suburban home, yet befriended a dancer he met in a downtown strip club and showered her with thousands of dollars in gifts.

"This guy isn't just leading a double life -- he's leading multiple lives," said Robert M. Blitzer, a former FBI counterintelligence official who worked with Hanssen. "You've got a religious guy and a family guy and an FBI agent, who is hanging around with strippers and spying for the Russians and all the rest. It's all so contradictory."

Hanssen, 57, pleaded guilty on Friday to 15 counts of espionage as part of an agreement with prosecutors. He will be sentenced to life in prison, rather than the death penalty, in exchange for giving the government a full account of the material he turned over to the Soviet KGB and its Russian successor, the SVR, while working as a top counterintelligence agent at the FBI.

U.S. intelligence officials hope the interrogations will allow them to determine the depth of Hanssen's betrayals, which included revealing to the KGB the identities of two U.S. double agents. They were later executed in Moscow.

The sessions also may provide clues to his motives. The public record so far, including court documents and interviews with family members, friends and colleagues, shows a man who viewed the world in moralistic black and white, yet was drawn to the grays of subterfuge, sin and redemption.

Money is said to be the most common motive for spying, and it clearly played some role in Hanssen's case. The Russians gave him $1.43 million in cash, diamonds and promised deposits in foreign bank accounts, and in his correspondence with Moscow he often discussed payments and ways of hiding the money.

The FBI originally believed Hanssen first approached the Soviets in 1985. He was then working in the FBI's New York office, where pay was so low that many agents were quitting.

"At this point, given the amount of money, cash and diamonds that Hanssen received, we have no question that he was motivated by greed," Assistant U.S. Attorney Randy I. Bellows, the lead prosecutor on the case, said after Hanssen's guilty plea Friday.

But many former colleagues and intelligence officials believe other factors drove Hanssen. Officials now know, for example, that Hanssen started spying for the Soviets in 1979, years before the height of the pay crisis.

Colleagues say Hanssen, a large man with hunched shoulders and a frequently sour demeanor, never seemed interested in material things. He drove a 1997 Ford Taurus, was noted for his shabby clothes and preferred cheeseburgers to fancier fare. Investigators still do not know what became of most of the money Moscow gave him.

"The pieces don't fit together on their own without a psychology driving things," said Moore, who car-pooled with Hanssen for years when both worked at FBI headquarters. "The money isn't enough to be worth it. The risks outweigh the benefits. He is making very calculated moves in what is a very dumb game."

Childhood Demons

A psychiatrist hired by Hanssen's defense team to analyze the accused spy traces many of Hanssen's troubles to his childhood, particularly physical and psychological abuse inflicted by his father, now dead. Alen J. Salerian, who was fired over disputes with the defense team, said Hanssen's strained relationship with his father colored his adult life.

"He was troubled, psychologically troubled, and he had demons," Salerian said in an interview.

Jerrold Post, a former CIA analyst who wrote a seminal paper on spy psychology, "The Anatomy of Treason," said flawed father-son relationships are often central to spy cases. Hanssen may have viewed the FBI as a father figure, Post said: He was outwardly respectful toward it, but privately aggrieved and plotting to undermine it.

Hanssen also had a complicated relationship with the Catholic Church and Opus Dei, a conservative Catholic group integral to his public and private lives.

An adult convert to Catholicism, Hanssen kept a silver crucifix above his desk when he worked at the State Department in the late 1990s and frequently signed out early to attend antiabortion rallies on the Mall. He interjected religion into everyday conversation and urged friends and colleagues to attend church.

Hanssen first confessed his espionage in 1979 or 1980 to a priest, who urged him to give the $13,000 he had just received from the Soviets to Mother Teresa, sources have said. Hanssen promised his wife, who had confronted him, that he would cease spying immediately. But officials indicated Friday that he continued selling secrets until 1981, then stopped for a few years.

After he began spying again in 1985, Hanssen repeatedly confessed to Catholic priests affiliated with Opus Dei, according to Salerian. "They just told him to keep praying, with disastrous results," Salerian said.

Fooling Everyone

By all indications, his family had no knowledge of his long-running espionage, despite his early admission to his wife. Family members have relied on newspapers to learn the details of what Hanssen was up to, according to people close to the family.

Hanssen's mother, Vivian, said Bonnie and the children are coping well. "Bonnie is taking care of things," Vivian Hanssen said. "Bob is lucky he's got her. The family is great."

Robert Hanssen's ego appears to be central to his subterfuge. He took pride in his knowledge of the intricacies of the spy trade, relying primarily on old-school methods such as "dead drops" to pass information back and forth. "I decided on this course when I was 14 years old," he wrote in one letter to his Russian handlers.

"A lot of these other spies -- if they weren't stealing secrets, they'd be stealing hubcaps," said James Bamford, a writer who became friends with Hanssen before his arrest. "But I think he wanted to be the perfect spy. He wanted to do Kim Philby one better and not get caught. It was almost like he had an addiction to it."

Post, the former CIA psychologist, said court documents indicate Hanssen reveled in his deceptions.

"There's a huge sense of superiority that comes through very clearly here: 'How immensely clever I am. The Soviets don't know who I am, the FBI doesn't have the vaguest idea of what I'm doing,' " Post said. "It's a game of solitaire that he's playing."

Or many games of solitaire: Spying was only one of Hanssen's many secrets.

In the summer of 1990, Hanssen began an unusual friendship with exotic dancer Priscilla Sue Galey. The relationship with Galey was as enigmatic as the rest of his life: He presented himself as an admirer of her grace and beauty, a father figure, a religious mentor and a devoted family man.

He implored her to go to church with him to find God and wanted her to leave the strip clubs for a "better life." Yet Hanssen also kept deep secrets from Galey -- as he did from everyone else -- at times intimidating her, puzzling her, fooling her.

"He was the paragon of virtue. He was the father I never knew," Galey said in an April interview. "How could he lie to my face like that about what kind of person he was? I put him on a pedestal, and I guess I was dead wrong. I would love to talk to him and ask him why he told me he was so perfect."

Galey said he gave her roughly $100,000 in gifts and cash, most of it shortly after he made secret pickups of thousands of dollars from the Russians. Two weeks after he retrieved an envelope containing $12,000 from one of his drop sites in July 1991, he gave Galey the keys to a Mercedes he bought for $10,500, asking for nothing in return.

"He told me he wanted to show me my place in the world," Galey said. "I never pushed, I never questioned it, and I guess no one else did, either. Maybe I should have."

Staff writers William Claiborne, Brooke A. Masters and Josh White contributed to this report.

Two boys play near the footbridge at Foxstone Park in Vienna, where Robert P. Hanssen was arrested in February shortly after allegedly leaving top secret documents there.Hanssen, above, "isn't just leading a double life -- he's leading multiple lives," said an ex-FBI counterintelligence official.