On Yom Kippur in 1929, Louis Fleisher, Harry Fleisher, and Henry Shorr attended services at Orthodox Congregation B'nai David in Northwest Detroit. The three men-all sterling members of the  Purple Gang, Detroit's mostly Jewish mob-had plenty to atone for: The Purple Gang controlled the city's illegal gambling, smuggled liquor during Prohibition, and had a hand in most of Detroit's underworld vice. The gang didn't hesitate to resort to violence-arson, bombings, and murder-when its operations were threatened. They were reputedly more ruthless than Chicago's Capone gang.

The three gangsters didn't notice three other men sitting in the back of the synagogue: G-men disguised in black Hasidic garb who hoped to arrest the three hoodlums after the service. But when the non-Jewish G-men lit up cigarettes during the intermission, not knowing that striking a match or lighting a fire is forbidden on Yom Kippur, their cover was blown and the gangsters got away.

The men of the Purple Gang weren't the only Jewish mobsters who observed Jewish rituals, even as they committed crimes that broke all of the Ten Commandments, as I discovered while doing research for my book on Jewish mobsters,  But He Was Good to His Mother: The Lives and Crimes of Jewish Gangsters. When examining FBI files and interviewing old-time Jewish criminals and their relatives, I found that plenty of Jewish mobsters prayed in synagogue on Shabbat, observed Jewish holidays, maintained religious rituals, fasted on Yom Kippur, and attended Passover Seders.

Sam "Red" Levine provides a singular illustration of this. Levine was New York City gangster Charley "Lucky" Luciano's favorite contract killer. According to Martin Gosch and Richard Hammer's 1975 book  The Last Testament of Lucky Luciano, Lucky called Red "the best driver and hitman I had." Red also had another persona: He was an Orthodox Jew. He always wore a kipah under his hat, ate only kosher food, and conscientiously observed the Sabbath. Levine never planned to murder anyone from Friday sundown to Saturday sundown. But, according to Gosch and Hammer, if Levine had no choice and had to make the hit on Shabbat, he would first put on a tallit, say his prayers, and then go and do the job.

Abner "Longy" Zwillman, dubbed the "Al Capone of New Jersey," reigned as king of the rackets in Newark from the Prohibition era to the 1950s. Next to Meyer Lansky, he was the most prominent Jewish mob boss in America. He reached this pinnacle through brains and violence. Despite his reputation as a ruthless mobster, Zwillman remained sensitive to his Jewish upbringing. Jerry Kugel-whose father Hymie was Longy's good friend-told me the following story when I interviewed him in 1991: When Hymie died, Zwillman stood outside and would not enter the chapel where the casket lay. Jerry could not understand this slight. He asked Zwillman why he wouldn't go into the funeral parlor. Zwillman replied that he couldn't. Why, asked Jerry. "Because I'm a kohen," said Zwillman; as a descendant of the priestly class, he was forbidden to come into contact with a dead body.

There are other examples from all around the country of Jewish gangsters obeying certain Jewish laws. How does one explain hoodlums, killers, vicious and violent men adhering to certain biblical injunctions? What about the Sixth Commandment, "You shall not murder," and the Eighth Commandment, "You shall not steal"? Why this paradox in their lives?

The Purples and most Jewish gangsters during Prohibition were the children of Eastern European Jewish immigrants who had come to the United States between 1881 and 1914. The mobsters had been born in America or came as kids. According to Arthur Hertzberg, in his 1997 book The Jews in America, most of their parents had not been part of the religious elite of their communities-the more pious and religiously Orthodox Jews heeded their rabbis' warnings that America was a trayfe medina (non-kosher land) and stayed behind in Europe. Nonetheless, the Jews who did immigrate came from places where the Jewish religion and Jewish traditions persisted as an integral part of the milieu. Most of the immigrants may not have been Orthodox according to Jewish law, but they maintained traditional Jewish religious patterns and brought these practices with them to America. Out of habit, a non-believing Jew might still observe the dietary laws at home, occasionally go to synagogue, and say kaddish for departed parents. These immigrants practiced what sociologist Charles Liebman, in his 1993 book The Ambivalent American Jew, called a kind of Jewish folk religion.

The Jewish mobsters grew up in these traditional homes in Jewish neighborhoods that were infused with folk Judaism, such as New York's Lower East Side, Chicago's West Side, and Detroit's East Side. And like many of their non-criminal peers, some of them continued these behavioral patterns into adulthood. Jewish ritual remained an indelible part of their identity, a part of who and what they were.

Perhaps the greatest influence on the "Jewishness" of these men were their mothers. Many of the major Jewish mobsters, including Meyer Lansky, Dutch Schultz, Lepke Buchalter, Longy Zwillman, and Mickey Cohen, as well as those I interviewed, revered their mothers. Family and friends recounted to me how these men doted on their mothers and treated them with utmost kindness and respect. In the 1979 book  Meyer Lansky: Mogul of the Mob, Lansky told Israeli journalist Uri Dan how his mother "hated to see us go hungry, and she was always ready to give us her share because, like every Jewish mother in the neighborhood, she gladly sacrificed herself for her children." These mens' relationship with their fathers was more problematic. Part of this resulted from the fathers never reconciling to their sons' criminal way of life.

Jewish mothers sacrificed for their children, but they expected something in return. One of their requests was that their sons sei Yidden (be Jews) and maintain a connection with the Jewish community. At least during their mothers' lifetime, a goodly number of these tough Jewish mobsters obeyed. Detroit mobster Harry Kasser told me in a 1986 conversation that he attended synagogue on the High Holidays solely to please his mother. All of the old-time Jewish mobsters I interviewed could speak Yiddish and practiced some of the Jewish customs. Most of their closest friends and associates in crime and outside of crime were Jews; they married Jewish women (at least their first wives) in ceremonies conducted by rabbis; they contributed to Jewish causes; they attended synagogue on the High Holidays; and they circumcised their sons and made bar mitzvahs.

Another factor contributing to the paradox in these mens' lives was their ability to separate what they did to earn a living-their "business" lives-and the way they behaved in their personal lives. Behaviorists refer to this as "compartmentalization": being able to act one way in the private world and another way in the public sphere, even if the result was blatantly inconsistent behavior. This paradox was expressed to me by a lawbreaker named Myron (he asked that I not use his family name). For years the FBI tried and failed to obtain a conviction against him. The Internal Revenue Service succeeded, however, and Myron ended up going to prison for income tax evasion. When we spoke in 1991, I asked him if he wanted his son to follow in his footsteps with all the dangers it entailed. He replied: "I would say to him that I chose my life, you go choose your life. The only thing is that whatever you choose to do, I would say to him, you gotta put on tefillin every morning, you gotta eat kosher meat, and you have to maintain certain principles."

Throughout their lives, Jewish mobsters remained products of their homes and the environments in which they grew up. Whether they believed in God or not, in adulthood they continued the Jewish traditions they learned as children. No matter how vile their later behavior, in each of these men there remained a pintele Yid, a spark of Jewishness. Meyer Lansky, the alleged godfather of Jewish organized crime, told me in 1980 that he was a non-believer. Yet he maintained his membership in a synagogue, regularly contributed money for its upkeep, and attended services on the Jewish holidays.

Labor racketeer Lepke Buchalter displayed similarly paradoxical behavior. He commanded an army of gangsters who terrorized New York's garment industry. His gang's weapons were destructive acids, bludgeons, blackjacks, knives, fire, ice picks, and guns. At his peak, he controlled a wide assortment of businesses and unions including the bakery and pastry drivers, the milliners, the garment workers, the poultry market, the taxicab business, the motion picture operators, and the fur truckers. Despite the murderous brutality he exercised in his business affairs, he was a considerate son and a doting husband and father. He described himself as a Jew, contributed money to his mother's synagogue, attended High Holiday services, and, according to the FBI, led a quiet home life.

The paradox sometimes lasted till the end of the mobster's life. Harry "Gyp the Blood" Horowitz was a vicious brute and killer of enormous strength, who thought nothing of breaking a man's back for fun. In 1914, he and three accomplices were convicted of murdering the gambler Herman Rosenthal and were sentenced to death. According to the April 18, 1914, edition of the Forward, after being strapped into the electric chair at Sing Sing, Gyp recited the Shema. When he finished, a jolt of electricity surged through his body, killing him instantly. One of his accomplices, Louis "Lefty Louie" Rosenberg, died in the electric chair holding a chumash.

Later in life many of the Jewish mobsters strayed far from the traditions of their youth. But almost all of them received Jewish burials at their death. Despite the brutal and illegal nature of the lives they led, at their demise many of these underworld figures still remained tied to their families, their people, and the Jewish tradition.