One call on the cell phone got us the address in Coconut Grove where Dr. Wilkins made his humble home. It was in a section called The Moorings, which meant that either my alma mater was paying professors a great deal more than they used to, or else Professor Wilkins had independent means. As we turned onto the street, the afternoon rain started, blowing across the road in slanted sheets, then slowing to a trickle, then picking up again.

We found the house easily. The number was on the yellow seven-foot wall that surrounded the house. A wrought-iron gate blocked off the driveway. Deborah pulled up in front and parked in the street, and we climbed out and looked through the gate. It was a rather modest home, no more than 4,000 square feet, and situated at least seventy-five yards from the water, so perhaps Wilkins wasn't really all that wealthy.

As we peeked in, looking for some way to signal the house that we had arrived and wished to enter, the front door swung open and a man came out, wearing a bright yellow rain suit. He headed for the car parked in the drive, a blue Lexus.

Deborah raised her voice and called out, "Professor? Professor Wilkins?" The man looked up at us from under the hood of his rain suit. "Yes?" "Can we speak to you for a moment, please?" Deborah said. He walked toward us slowly, head cocked at Deborah on a slight angle. "That depends. Who is us?"

Deborah reached into her pocket for her badge and Professor Wilkins paused cautiously, no doubt worried that she might pull out a hand grenade. "Us is the police," I reassured him.

"Is we?" he said, and he turned toward me with a half smile that froze when he saw me, flickered, and then resumed as a very poor fake smile. Since I am an expert on faking emotions and expressions I was in absolutely no doubt about it-the sight of little old me had startled him somehow, and he was covering it by pretending to smile. But why? If he was guilty, surely the thought of police at the gate would be worse than Dexter at the door. But instead he looked at Deborah and said, "Oh, yes, we met once before, outside my office."

"That's right," said Deborah as she finally fished out her badge. "I'm sorry, will this take long? I'm kind of in a hurry," he said. "We have just a couple of questions, Professor," Deborah said. "It will take only a minute."

"Well," he said, looking from the badge to my face and then quickly away again. "All right." He opened the gate and held it wide. "Would you like to come in?" Even though we were already soaked to the skin, it seemed like a pretty good idea to get out of the rain, and we followed Wilkins through the gate, up the driveway, and into his house.