Shannon Coyle is the daughter of Susan Coyle and the brother of Brian Coyle, as well as the girlfriend of Aidan Connor, who unknown to her was her half-brother.
History[]
Susan made up an imaginary "father" named Barry to hide Shannon being born from an affair between Susan and Aidan's father Jason Connor. Much later, Susan and Jason were horrified and panicked when Shannon and Aidan, unaware they were half-siblings, began to date and eventually have sex, so the two families forbade Shannon and Aidan from being together. It didn't work, and the two continue to maintain a relationship. Shannon panicked when she got pregnant and spoke to Jason who met her in secret. By his own account, Jason revealed the truth of the affair to Shannon, which caused her to have a mental breakdown. When Jason begged Shannon to forgive him, she pushed him away, fell back, and died by cracking her head.
A horrified Jason placed a tarp on her and told Susan everything, and they left Shannon to be found in an alleyway while the couple was planning to leave the country so Jason could leave his wife Debra Connor for Susan. Debra shot Jason dead out of revenge for the affair, and Aidan had a mental breakdown finding out the truth about his family and relationship. When Aidan confessed out of mental instability from his grief, Debra confessed her true role in Jason's murder and let herself be arrested. Susan was arrested as an accessory to Shannon's murder, and Aidan was left to speak with Shannon's brother Brian Coyle about what to do next. (SVU: "Families")