She was played by Aida Turturro, who is best known for playing Janice Soprano on The Sopranos.
Bobbi is the daughter of Carl Catalano, who was found dead in a cemetery. During the investigation, Allison has vivid nightmares which feature her as Barbara, the lead character in the 1968 classic, Night of the Living Dead. In one of them, she wakes up with a bite mark on her right arm, and in another, she runs into a garage containing tanks of formaldehyde. These same tanks are shown in Allison's latest meeting with Bobbi, who accidentally burns her right arm; leaving a mark similar to the one Allison has.
After also learning that "Bobbi" is short for "Barbara," Bobbi is called back for an interrogation, where it is revealed that she actually killed her father. Bobbi had been selling formaldehyde to drug dealers to use as part of drug known as "wet," and when Carl, who had been fighting against the wave of drugs in the community, found out about his daughter's misdeeds, he confronted her. The confrontation took place at the cemetery at the grave of Bobbi's mother; there was a struggle, and Carl bit Bobbi, who later killed Carl. To cover her tracks, the evil Bobbi attempted to pin her father's murder on a homeless drug user named Edgar Kripke.