She yelled after him, “Leppo!”—calling his name down the hallway over the barefoot killer she had shot dead. The soles of his feet were dirty, almost black, and that made it somewhat more tragic; sordid.

He was gone. And for a moment she was alone in the blue flashing hallway with the man she had shot.

Odessa felt sick. It was different from the nausea she’d experienced upon discovering Mrs. Peters’s savaged corpse. Most FBI agents never fire their sidearm in the line of duty. There was going to be an inquest. Thank God she had Leppo as an eyewitness.

Odessa stepped around Peters’s corpse, unable to look away as she passed. His bloodstained hands still lay over his chest wounds, his eyes staring straight up at the ceiling and beyond.

She approached the bedroom with her gun lowered, not wanting to scare the surviving Peters child. She stepped into the open doorway Leppo had moved through.

The nine-year-old girl wore warm soft-yellow pajamas covered with images of cartoon baby chicks hatching from smiling white eggs. Walt Leppo stood just behind her, holding a handful of her blond hair in his fist. Her mouth was open but no scream came out. Her body was twisted, trying to pull away from Leppo, but her hair was firmly in his grip.

Leppo’s other hand gripped the carving knife, not as one would handle a vital piece of evidence, but wielding it like a weapon, blade pointing down.

Odessa’s mind tried to bring order to what she was witnessing: Maybe Leppo is holding the girl in order to keep her from running off. He’s only trying to prevent her from seeing her father’s dead body out in the hallway, and the bodies of her brother, sister, and mother.

But this split-second rationalization did not match up with the look she saw on Leppo’s face. The doll-eyed menace, his twisted grin. It was almost as though he were showing the girl the knife and its blood-slicked blade.

“Leppo?” said Odessa.

It didn’t make sense. Leppo did not seem to even know Odessa was in the room with him. He lifted the knife, turning his head to look at the blade himself, while the girl bucked her head, trying to break his strong grip.

“Walt, put it down,” said Odessa. “Walt! Put the knife down!”

She couldn’t believe she was saying these words. Odessa found herself aiming her Glock at him. She was drawing down on a fellow agent. It went against every instinct she had.

Leppo looked back at the girl. He yanked her hair back even harder, leaving her tender throat fully exposed. Something was very wrong.

In that moment, Odessa could feel what was going to come next.

“LEPPO!” Odessa screamed.