On April 17, 1990, Richard and Nancy Langert were murdered in their home in Winnetka, Ill. A 16-year-old boy shot Richard in the back of the head, and as Nancy huddled in a corner of their townhouse, the teenager shot her in the abdomen, killing both her and her unborn child.

As captured in Change of Heart: Justice, Mercy, and Making Peace with My Sister’s Killer (Westminster John Knox, Feb.), the event also changed the life of Jeanne Bishop, Nancy Langert’s sister. When the killer was convicted and received a sentence of life without parole, Bishop--then 29 and a corporate attorney--felt satisfaction and relief, and she vowed never to speak his name, calling it “almost a way of killing him.” But as she details in the book--part memoir, part call for change--an unexpected turn would later see her working to secure the murderer's parole, and campaigning against what she calls "merciless sentences" for juvenile offenders.

Twenty years after the conviction, Bishop was picnicking with her sons, then 7 and 11 years old, when Brendan, the oldest, said they had to forgive the man who had killed Aunt Nancy and Uncle Richard because “God made him for a purpose.” Bishop was struck by the truth of the child's statement.

Soon after that conversation, Bishop—who had coincidentally become a public defender just months after the murders—read two books that changed her mind about mandatory life sentences for juvenile offenders. One of the authors, Randall O’Brien, in a chapter titled “Forgiveness: Taking the Word to Heart” (Forgiveness: Christian Reflection, Center for Christian Ethics at Baylor University, 2001), wrote that no one is relieved of the obligation to work for reconciliation. But Bishop didn’t think that could possibly apply to her, so she called O’Brien, and as they talked her views began to change. “I realized I called myself a Christian, but never once had prayed for this young man,” she says.

Bishop eventually wrote her sister’s murderer a letter of forgiveness and offered to see him. He responded with 15 pages that included an apology, finally taking responsibility for the crime, when during the trial he had denied everything. She understood that “he was young and scared,” and that while forgiveness had really been about her, reconciliation moved the focus to the killer, saying “it is also about you.” Bishop decided to work on behalf of the killer to gain his parole.

She now will speak the name of David Biro, noting that at the time of the murders he was a skinny kid with brown hair and is now a 6’ 5” man with tattoos and a receding hairline. Many find the fact she is working for his parole inexplicable, attacking her as “delusional,” “feeble-minded,” and a “sicko,” she says. But she believes that because 16-year-olds “are not thinking or pondering consequences,” they should have a second chance. “The system needs to be about rehab and redemption, and not retribution alone.”