[1] When the family arrived in New York, they began a series of small businesses, taking in goods collected by scavengers and reselling them.

Mandelbaum began financing thieves and burglars and was involved in planning some of the biggest thefts in the city's history, including the Ocean National Bank.

According to police inspector Thomas Byrnes in his 1886 book Professional Criminals of America, Mandelbaum’s known associates included "burglar" Michael Kurtz (“A Jew.

[8] Mandelbaum also became one of New York's most prominent hostesses of New York's high society, as well as the underworld, regularly associating with some of the most well-known criminals of the day including Queen Liz, Big Mary, "Black" Lena Kleinschmidt, Adam Worth, Sophie Lyons, and George Leonidas Leslie as well as judges and police officials.

[citation needed] Mandelbaum’s preferred items were bolts of silk and diamonds, which she could acquire inexpensively and sell at a significant profit.

Her increasing infamy led to numerous mentions and quotes in newspapers, and her ostentatious display of wealth made her a notable and recognizable character.

[8] Mandelbaum often adorned herself with $40,000 worth of jewels and dressed in luxurious materials such as silk, ostrich feathers, and sealskin, making her "hard to miss".

Her arrest in July and subsequent case received extensive coverage from major New York newspapers, intrigued by the downfall of such a notorious criminal.

At the time there was no extradition treaty between Canada and the United States, so she lived out her remaining years there, despite expressing regret over leaving New York, once telling a reporter, “I am sorry that I ever left New-York, I should have faced the music.”[7] Mandelbaum died in 1894.

The press may have found irony in calling a woman, often described with antisemitic overtones as “a German Jewess with large, coarse features, almost masculine in appearance, restless black eyes, and a dark, florid complexion,” "Mother."

[7] The Brooklyn Daily Eagle described Mandelbaum, possibly with a hint of irony, as "a most respectable and philanthropic receiver of stolen goods in New York.