Then a fourth body turned up.

This time the scene was staged differently. The victim had been left on a park bench in the predawn hour, the ribbon looped in a large bow over a lamppost as if someone had punctuated a sentence for the city to read. The victim was a woman who had worked in a small theater collective, someone who had been friendly with Jonah. Her scarf had been tied in the same knot.

Forensic psychologists have long debated the significance of the color choice in the Red Garrote murders. Why red, specifically?

"I didn't kill them," he said. "But I watched them at a remove. They let me. They wanted to be seen."

A year later, the mural had brightened with new additions—names, flowers, and a loop of red painted across the corner where someone had left fresh paint like a benediction. People passed it and sometimes paused. They looked.