WASHINGTON -- For a man accused of betraying his country to the godless leadership of the Soviet Communist Party, Robert Philip Hanssen could not have seemed a more devout follower of the Roman Catholic Church - or a more committed anti-Communist.
He often told his friends in the Counterintelligence Division of the FBI, where he worked for most of his 25-year career with the bureau, that he loathed Communism and that the teachings of Lenin were incompatible with those of Jesus Christ.
"Bob would walk into my office and tell me that without religion, man is lost," said his former FBI supervisor, David Major, "and that the Soviet Union would ultimately fail because it was run by the godless Communists. And I believe he was sincere."
The bureau's former chief China analyst, Paul D. Moore, recalled that when FBI agents held going-away parties at strip clubs near the bureau's headquarters in Washington, Hanssen refused to attend, saying his faith would not permit it.
"He said, 'You shouldn't do that because it's an occasion of sin,' " said Moore, who used to car pool to work with Hanssen, a friend of 20 years.
He recalled Hanssen snapping off the car radio one day during a talk-show conversation about morality - and whether morality was based on social contracts.
"He leaned over and turned off the radio and said, 'That's enough of that,' " Moore said. "He said the foundation for morality is not an implied social contract; it's God's law."
If Hanssen's piety and staunch anti-Communism were simply a front for his treachery, if they were a cover for a long career in espionage, they were remarkably convincing to the professional spy catchers who worked day in and day out with the shy, socially awkward, highly intelligent agent.
Hanssen could face the death penalty after his arrest Monday on charges of spying since 1985, initially for the Soviet Union and then, after its collapse, for Russia. He was apprehended after he supposedly dropped off secret documents at a park near his home in Vienna, Va.
The case is described by officials as potentially the worst intelligence breach in the bureau's history, given Hanssen's access to some of the most highly classified information in the computer banks of the FBI. The bureau has said that at least two Russian double agents who were executed may have been exposed because of his disclosures.
In his quarter-century at the FBI - at the time of his arrest, he was only a few months from retirement - Hanssen gave every appearance of living the life of a God-fearing Christian.
When he worked in the fourth-floor offices of the Counterintelligence Division at FBI headquarters in the 1980s, colleagues remembered that he would sometimes leave his cubicle for an hour to attend Mass at a downtown church.
Every Sunday for years, Hanssen and his wife, Bonnie, a teacher, were found in the same left-side pew near the altar of St. Catherine of Siena Catholic Church in Great Falls, Va.
The Hanssens told friends they selected the church because it was one of the few in the region that still conducted a Latin Mass, and they preferred a traditional service.
Among the church's other regular parishioners: Louis J. Freeh, the director of the FBI, and Justice Antonin Scalia of the Supreme Court. (Freeh said through a spokesman that he knew the Hanssens through a handful of contacts at the church but was never a "social friend" of the couple's.)
The Hanssens were adherents of Opus Dei, an elite conservative Catholic order. Opus Dei urges its members to attend daily Mass, and Hanssen also regularly appeared for evening prayer-and-confession sessions known as recollections.
While the Hanssens lived in a suburb of Washington known for the quality of its public schools, they chose instead to send their six children - three boys and three girls - to expensive private schools affiliated with Opus Dei.
Former colleagues said they would be shocked if Hanssen turned out to have spent the money he is accused of having received from his handlers in Moscow - at least $600,000 in cash, the FBI says - on alcohol or fancy automobiles or women. Instead, they suspect, he probably used much of the proceeds from his spying to pay tuition at his children's schools.
The Heights School of Potomac, Md., which his youngest son, a junior, attends, charges annual tuition and fees of nearly $11,000, which alone would make a large dent in Hanssen's FBI salary of about $100,000 a year.
His older sons also graduated from the school, which will not say if any of the boys received financial aid.
In interviews since his arrest, many of Hanssen's closest friends and colleagues, dumbfounded by the spying accusations, say they can only offer a guess as to why a man so committed to his faith might have volunteered for espionage on behalf of the political system that was long considered organized religion's greatest enemy.
Several suggest that Hanssen must have been able to completely compartmentalize his life, deluding himself into thinking that espionage was simply an exciting intellectual challenge that had nothing to do with leading a good, moral Christian life.
"I think Bob was able to bifurcate his life," said Major, his former supervisor.
"He somehow made the intellectual leap, which I just cannot rationalize, that the compromise of information was somehow OK, and that it was just a game. It's too simple to say thrill, but I do believe that he was in for the game, not the gain."
FBI officials say that Hanssen's career stalled years ago, and that resentment over his failure to rise higher in management despite his obvious intelligence could have been a factor in his decision to spy.
But many who know Hanssen say that it was clearly not the full explanation and that he complained far less than other agents about troubles with his career.
Richard McPherson, a fellow member of Opus Dei and the headmaster of the Heights School, said he continued to believe that Hanssen's shows of piety and his lack of interest in material goods "were not some sort of cover."
He remembered Hanssen's devotion to his children, and how he volunteered for school dances, where he served as a chaperon, and attended his sons' sporting events.
"I thought he was a great father, a good husband and a good professional," McPherson said.
"Of course, if he did what he is purported to have done, then he was living a lie as a Christian and a citizen. But I'm still hoping there's an explanation."