"Clues," I said. "An overheard snatch of conversation. A subrosa glimpse of a secret bank account. Something that I can use in ascertaining the nature of the crime." I hadn't used ascertaining in three or four weeks.

She said, "Are you making fun of me?"

I was getting one of those headaches that you get when your blood sugar starts to drop. "No, I'm trying to make you consider what you want and why you want it. You claim that Mark Thurman is involved in criminal activity, but you have no direction in which to point me. That means that you're asking me to surveil an active-duty police officer. Police officers are paranoid by nature and they move around a lot. This will be expensive."

She looked uncertain. "How expensive?"

"Two thousand dollars. In advance."

You could see her swallow. "Do you take Visa?"

"I'm afraid not."

She swallowed a second time. "That seems an awful lot."

"Yes," I said. "It is."

She put the photograph of Mark Thurman back in her purse and took out a red doeskin wallet. She dug in the wallet and got a faraway look like she was working with numbers. Then she pulled out two twenties and put them on my desk. "I can pay you forty dollars now, and forty dollars per month for forty-nine months."

I said, "Jesus Christ, Ms. Sheridan."

She clenched her jaw and brought out another ten. "All right. Fifty dollars."

I raised my hands, got up, and went to the glass doors that lead out to the little balcony. The doors that came with the office were aluminum sliders, but a couple of years ago I had them changed to a nice set of double-glazed French doors with brass handles. I opened the doors, set them so that the breeze wouldn't blow them closed, and that's when I saw two guys sitting across the street in a brown unmarked sedan four stories below. A tall guy with shaggy, thick-cut hair sat behind the steering wheel and a shorter guy with a ragged face slouched in the passenger's side. The tall guy had long forearms and a ropey neck and looked a lot like Mark Thurman. Sonofagun. I turned away from the doors and looked at Jennifer Sheridan. Nope. She didn't know that they were out there. "Mark work today?"

She looked surprised that I'd ask "That's right. He works Monday through Friday, from eleven until six."

"He let his hair grow since he went to REACT?"

Jennifer Sheridan smiled, trying to figure me. "Why, yes. He had to, for the undercover work"

Thurman, all right.

I walked back to the desk and looked at her. You could see how much she loved him. You could see that she trusted him, and that she'd never think that maybe he was following her. I said, "Do you and Mark live together?"