She was born at Sant Feliu de Llobregat in 1868, moved to Barcelona as a young woman, and lived in the poorest part of the old city. She worked as a servant, then as a procuress, and had convictions connected with prostitution.
On February 27, 1912 a neighbour in the Carrer Ponent recognised a child at her window as Teresita Guitart Congost, five years old, who had disappeared eleven days earlier. The police found Teresita in the flat with her head shaved, and another girl, Angelita, whom Marti claimed as her daughter. In the flat and in other rooms she had rented, police reported finding children's clothing, bones and jars of preparations. The Spanish press called her the Vampire of Barcelona.
What followed was one of the great press campaigns of early twentieth-century Spain. Barcelona newspapers reported that she had killed dozens of children and rendered their bodies into ointments and potions sold to wealthy clients as cures for tuberculosis, and named her the Vampire of the Raval. Nothing of that was tested. She was never tried. She died in the Reina Amalia prison on May 12, 1913, reportedly killed by other inmates, though prison records give illness.
The historian Elsa Plaza, working from the surviving court and press files, has argued that most of the legend was manufactured, that the remains found were not shown to be children's, and that the campaign served a city that wanted a monster rather than an account of how its children came to be missing at all. The abduction of Teresita Guitart is documented. The figure of ten or more in this roster is not. The entry is kept because the case is historically significant, and it should be read as a press phenomenon at least as much as a criminal one.