Thieves cash in with the aid of those dealers in dubious goods known as fences. In the male-dominated underworld of the Gilded Age, New York’s leading fence was female. Her success was as straightforward as the woman herself: She was honest in her dealings and a shrewd judge of character. Between 1864 and 1884, most New York robbers, burglars, and bandits made the most of their ill-gotten gains by trusting Mother Mandelbaum, who handled as much as $10 million in swag – roughly equivalent to between $120 million and $200 million today.

Frederika “Mother” Mandelbaum, better known as Marm, was born in Germany around 1830. Her name reportedly first appears in police records in 1862 for peddling stolen merchandise door to door. She graduated to managing teams of pickpockets, processing their takings while providing bail and legal defense. By 1864, she owned 79 Clinton St., a three-story building at the corner of Rivington Street. The family’s haberdashery, managed by her husband Wolfe and their three children, had a back room for her real business: reselling pinched products to nominally legitimate businessmen across the city. She rarely touched the loot – instead, an operative looked it over at a neutral location. Anything accepted had to be stripped of labels, tags, and private marks prior to delivery.

The Mandelbaums lived above their store, in rooms elegantly furnished by her clients with furniture and draperies from some of New York’s finest mansions. A warm, generous hostess, she held frequent dances and dinners attended by celebrated criminals as well as friendly politicians and cops. Marm allegedly ran a school on Grand Street in the manner of Dickens’s Fagin, where boys and girls were taught useful tricks by professional pickpockets and sneak thieves, with advanced courses in burglary and safecracking and postgraduate work in blackmail and con games. Some modern feminist historians express admiration for Marm for mentoring women criminals such as con woman Sophie Lyons and pickpocket Black Lena Kleinschmidt early in their careers.

From fencing goods, Mandelbaum progressed to financing bank robberies, including New York’s first great bank robbery, the Manhattan Savings Institution caper of October 1878. Planned by George Leonidas Leslie, nicknamed Western George, the heist was three years from conception to execution. Leslie led a double life: elegant, literate man-about-town and professional pilferer. A mechanical engineer by training, Leslie’s robberies went far beyond the stick-’em-up by involving the procurement or creation of architect’s drawings of the banks to be robbed and the fabrication of customized tools for each job. With Marm’s money, Leslie even purchased a duplicate of the bank’s vault to test for weaknesses. Bribing Manhattan Savings’ watchman Patrick Shevlin enabled Leslie to hold practice runs inside the bank after business hours.

But in June 1878, four months before the robbery, Leslie’s partially decomposed body was found on Tramp’s Rock in the Bronx, near the Westchester County line. The general consensus is that Leslie, having talked too much, was popped by his own gang as a punishment. Mandelbaum paid for the funeral. Leslie’s death was no barrier to executing his perfect plan. But only $262,000 of the loot was in cash and freely negotiable bearer bonds. The rest of the $2.75 million taken was registered securities, which were essentially worthless as they could not be freely transferred.

Local precinct captain Thomas F. Byrnes interrogated the guard, Shevlin. As Shevlin had received only $1,200 of a promised $250,000 for his help, and as Byrnes was a master of both psychology and the third degree, the watchman talked. Byrnes arrested most of the robbers, although he couldn’t touch Marm. But Manhattan District Attorney Peter Olney did. Olney wisely mistrusted the police. He hired Pinkerton detectives who attached secret identifying marks to property left open for stealing by Marm’s clients. The setup worked: On July 22, 1884, Marm’s house was searched. Marm was arrested and released on $21,000 bail, supposedly secured by her real property.

Her lawyers were the roguish William F. Howe and Abraham Hummel, popularly known as Howe the Lawyer and Little Abe, who represented what Richard Rovere called “the upper crust of the lower order.” Just before her trial in December 1884, Marm skipped to Canada with more than $1 million in cash. When the authorities tried seizing the property pledged for her bail, they found title had been somehow transferred to her daughters years earlier. In fact, Little Abe had fraudulently backdated the deeds. He had also taken care of his law firm: Rovere states, “Howe and Hummel were asked if she had left town without settling her account with them. Howe replied, according to the story, by looking ‘toward the ceiling and jingling some silver in his pocket. Lawyer Hummel, also looking heavenward, softly hummed a tune.'”

As America then had no extradition treaty with Canada, there Marm remained, dying in Hamilton, Ontario, on February 26, 1894.