The Butterfly Murders by Jen Talty

Special Agent Kara Martin has spent the last thirteen years doing whatever she could to obliterate memories of her hometown…and haunting reminders of her parents’ murders. She had every intent of avoiding Rochester…until a congressman’s daughter is murdered, and she finds herself not only back to a place she said she’d never return, but working with a man she thought she’d never see again.
A man who once loved her… until she broke his heart.
Detective Shane Rogers lost his wife and a year later nearly lost his son when his rare heart condition took a turn for the worst. Battling back from personal devastation, his son is now thriving after a successful heart transplant and Shane can finally return to his second love…his career as a homicide detective.
His first case is the gruesome murder of a local congressman’s fourteen-year-old daughter, bringing in the FBI and putting Shane face to face with his first love.
Shane and Kara are thrust together in one of the toughest cases of their careers while pieces of their pasts crop up to taunt them.
As they begin to face their pasts and find forgiveness, the bodies pile up. With each new murder, the killer takes a different organ that is commonly harvested. An organ they had received in the form of a transplant.
And now Shane’s son has been kidnapped…