From The Vintage News:
At the beginning of the 20th century, Enriqueta Martí — a woman from the witchcraft-steeped countryside of Cataluña — came to Barcelona. Rather than “The Pearl of the Mediterranean” she saw Barcelona as “The City of Death”. In the evenings she worked as a prostitute, and during the day she begged for charity. She imposed the same schedule to the children on the street who she used as her own while she begged, the same children who she introduced to prostitution.
It is suspected that she kidnapped a large number of children over a span of twenty years. Martí was never tried for her crimes. She died a year and three months after her arrest at the hands of her prison mates.