“Okay, here’s what McKenzie found out.” David took a deep breath. The room was dark, but he knew who the other person was. “There is only one janitor. It’s the same guy every night for five years. He almost never takes the day off, and when he does, no one replaces him.”

“So that way’s out,” Collins said. David didn’t need an explanation.

“Yeah.”

“Fine. What else do we know about the cleaning?”

“The museum pays ...