“For fifty bucks, I don’t think he asked a lot of questions. He couldn’t give us any kind of useful description. Tall. Lean. That’s it.” Frost added, “What about you, Herb? Have you spotted anyone hanging around in a mask like this among your crowds?”

“No, but why would I?”

“Because of me,” Frost said. “He knows I’m the one investigating the case, and he seems to be making it personal.”

Herb put Shack on the ground, and the cat sprawled on the sidewalk between them. “How can I help?”

Frost took his phone out of his pocket and clicked over to his photos. “This is a photo of Lucy,” he said, showing the picture to Herb. “This guy had to get her from her apartment to wherever he’s hiding. Maybe someone saw them.”

“You want me to put the word out to my network?” Herb asked.

“Exactly.”

Herb had fingers in nearly every corner of San Francisco, thanks to his years on the city council. Five years earlier, he’d also pioneered a nonprofit initiative to get donated smartphones in the hands of every homeless person in San Francisco. The phones had become a lifeline for jobs, housing opportunities, food, and city services—and they’d also become ground zero for a social media network that could get news around the Bay Area almost instantaneously. Among Herb’s twenty-seven thousand Twitter followers were more than five thousand homeless people who were 24-7 eyewitnesses to city life. They didn’t always trust the police, but they trusted Herb.

“What would you like me to tell them?”

“I’ll text you Lucy’s photo,” Frost said. “I’ll send photos of the other three women, too. I’m hoping someone spotted them going in or out of this guy’s hiding place.”

“Consider it done. I’ll get something out immediately.”

“There’s one other thing. A song. ‘Nightingale’ by Carole King. Do you know it?”

“Of course,” Herb said. “Carole cowrote it with David Palmer. He was lead singer for a few of the songs on Steely Dan’s first album. That’s your music trivia for the day.”

Frost smiled. There was very little trivia from the ’60s and ’70s that Herb didn’t know. He’d grown up in San Francisco during the days of flower power and the Summer of Love.

“‘Nightingale’ was used as a trigger with the women who died. This isn’t a Taylor Swift song that gets played thousands of times a day. If anybody heard that song recently, I’d like to know where.”

“I’ll put out the word, but once I do, the press is likely to get hold of the story. They follow whatever I post on Twitter, and I get calls. Is that okay?”

“That’s fine. Jess wants to make it all public. The Night Bird. The song. If anybody calls, send them my way.”