Bonnie Pearl Gunnarsen is the older sister of Harvey, as well as his only sibling. Being 6 years apart in age, she hardly wanted to be around her brother, and the two often fought each other. Haughty in personality, there'd been times when Bonnie treated Harvey with contempt, as she wished for a younger sister instead of a brother. Yet as the years went by, she learned to love Harvey in her own way.
In 1933, a rival Irish gang broke into the Gunnarsen's home and kidnapped the Gunnarsen siblings. The gang put Bonnie into one of their rackets, where they worked her as an indentured servant at a mob-owned brothel in New York. The grueling mob life took a toll on Bonnie and hardened her views on crime. The moment she turned 18, she sought to eliminate the women of the brothel who treated her poorly. With some careful scheming, she poisoned the one who treated her the worst—her Madam—and blackmailed the politician her madam was with. Bonnie then rose as the new Madam of the brothel.
She gained the nickname of 'The Pearl Gunn' from the pearl-handled Colt 1903 handgun she always carried with her. It is a play on her birth name; eventually, she used 'Madam Pearl' as her stage name when she took over as Madam. When the Feds shut down her bordello, she opened a new one in Chicago and named it after her nickname. She also made the club more elegant, offering quality wine and cigars. She advertised to have girls work in her club as cabaret performers, but to no avail.
A few years later, she became the mistress of a Chicago Outfit enforcer named Felix Alderisio. Seeing Bonnie struggle to maintain revenue for her operation, Felix offered to supply her with the girls she needed in exchange for being the co-owner of the club. Thus, Bonnie's club got incorporated into Felix's prostitution racket. The club became known not only as a high-class cabaret venue, but also as a place for the rich to unleash their primal desires...
In 1955, Bonnie had a falling out with Felix over a huge disagreement on club management. Refusing to sleep with him, Felix held Bonnie at gunpoint, threatening to shut down the club if she didn't cooperate. Fearing for her life, Bonnie secretly called the police, and an undercover investigation took place. Around this time, Harvey finally found Bonnie and rescued her, thanks to the joint effort of the FBI and local law enforcement. They eradicated the club, putting a stop to its illegal operations. Although Bonnie came out with an innocent verdict in the following trial, she refused to return to Harvey and the rest of their family. Instead, she fled to the UK to start a new life away from the mob.