“I was assigned to her and fell in love with her,” Chief Jaffe recalled.

That night, Officer Jaffe asked to take the baby home, but child welfare services instead arranged for Christina to stay with a foster family in Coney Island. Two detectives rode in the front, with Christina and Officer Jaffe in the back — an image of which was on newsstands the next morning in what could be called their first family photo.

Christina would be reunited with her father, a building superintendent in Manhattan, but was sent to live with her grandmother Felicia Rivera. Christina grew up on a bad block in Washington Heights in Upper Manhattan, her grandmother devoted but overprotective. She was not told what had happened that Palm Sunday. Her grandmother once mentioned that Christina’s mother had asthma; from that, the girl concluded, her mother must have died of an asthma attack.

The truth came out when she was about 10. One day, Christina came home from school agitated: A girl told her that her mother had been murdered.

“Are you ready for this?” her grandmother asked.

A gray suitcase emerged, stuffed with laminated newspaper clippings, telling of the murder of not only her mother but of two siblings she never even knew she had. One of the articles had a diagram of where the victims were found, some in front of the television, others napping on a bed. Christina fixated on the woman with the spoon, she said. “I remember focusing on that detail,” she recalled. “Who were they feeding?”

By then, Chief Jaffe said, she was already a presence in Christina’s life. She would drop in to play with Christina, leaving behind a gift for the child and some spending money for the grandmother.

In vague terms, Christina was told by her grandmother that Chief Jaffe “had been there from the beginning.” Slowly, Christina began to realize what her grandmother meant.