The most widely accepted legend is that Isabel left her house as a young teenager to live with a wealthy man, only to find out that he was married. She then started to date another wealthy man, a much older, American man. While Isabel was happy with him for some time, he grew disrespectful of Isabel's Puerto Rican traditions. On Saints Day, a typical Latin American holiday, he blew out the candles she had lit to honor the saints.
After this episode, she left him and returned home, only to find out that her home was now being used as a brothel. Isabel, maybe being naive, at first did not know the women occupying her house were selling their bodies to men, as she thought they were giving out sex only because they liked it. However, soon she discovered they were selling themselves, and she began to do business in prostitution.
Isabel la Negra then declared herself Madame of her brothel. With time, she would become one of the first women to become an important figure in the mafia organizations, controlling a lot of areas such as drug trafficking and other illegal activities. According to legend also, Ponce's mayor was one of her prostitution clients, and the Navy had considered signing with her so that their soldiers would use her brothel's services exclusively when they were in Ponce.
Before she was murdered, her nickname had become a household name all over Puerto Rico and she had become a legend, as many of her criminal activities were documented on the newspapers, tv and radio. Even after she died, her legend continued on growing. Some even consider her an example of the feminist movement in Puerto Rico.
Writer Mayra Santos Febres has announced that she is writing a novel based on Luberza Oppenheimer's life.