“People who lie often tuck in kernels of truth,” Frost said. “Sometimes they do it unconsciously, because the truth is so familiar to them. Other times it’s a taunt. Or they may find it’s easier to build a fake story on top of something that’s real.”

She tried to remember what Todd had told her. Then and now. “He said he did freelance tech work. He mentioned some kind of tech start-up near SF State that was like an Uber for computer support. He worked for them.”

“We’ll check it out,” Frost said. “He was a tech wizard, no doubt about that. He built an elaborate setup inside that room, and he had to have a lot of experience to pull off something like that. It must have taken him weeks of planning.”

“What else?” Jess asked her. “The Night Bird is still out there, Dr. Stein, and you’re our only link to him.”

Frankie shook her head. “I’m sorry, I don’t remember much. It was months ago.”

“Why did he come to you in the first place?” she asked.

“He said he’d been bullied as a child by one of his cousins. He had a boss whose treatment at work was bringing the memories back.”

“Do you think any of that was true?” Frost asked.

“Knowing what I know about him now? No. If I had to guess, he used someone else’s story and pretended that it was his own. He wanted to get into my treatment room. He wanted to see exactly how I worked with people’s memories. The whole thing was a way to spy on me.”

“He learned his lessons,” Frost said.

Yes, that was true. Todd was smart. He’d figured out exactly how to lead her down the path he wanted her to follow. How to make her play his game move by move. The unexpected meetings outside the office, designed to startle her and keep her off balance. The fake horror of his memories of torture, perfectly timed with the deaths of Brynn Lansing and Christie Parke. He fed her the clues, and she put them together.

“Todd was the one who led me to Darren Newman in the first place,” Frankie recalled. “He knew I’d recognize Darren in the videos he gave me. I saw him in that men’s room in the bar, and I leaped to the conclusion that Darren was stalking Todd. Which was exactly what he wanted me to believe. I never dreamed that it was the other way around. Todd was stalking Darren. He probably bumped into Darren and stole the button off his sport coat, too. So you could find it, and I could see Darren wearing the coat with the missing button. He covered all the bases.”

Jess said, “Videos?”