We went up the front-hall stairs to the second floor, which held six bedrooms, three on either side of a long hall, with another full bath at the back, the end that overlooked the fields to the north. The only sign of use in the bathroom was a bottle of All Ways shampoo in the walk-in shower.

The rooms were presumably the ones McKinnon had rented to the Ferrings and other African-Americans back in the fifties and sixties. Four stood vacant now of everything but their narrow bedsteads, chenille spreads laid over bare mattresses, empty deal chests lined with shelf paper.

The two bedrooms at the front of the house were the biggest, and they’d been used recently: the beds were fully made up, the radiators were on, and towels hung on racks by the doors.

I took off my windbreaker and wrapped my hand in it to pull open the bureau drawers. In the east room, the most carefully decorated room in the house, with sunflower-bedecked wallpaper and curtains, I found a bra and two pairs of panties in one drawer. La Perla. The owner—Emerald?—must have taken off in a hurry. Each wisp of Italian lace sets you back a few hundred dollars. I ran my fingers across the delicate fabric, then on impulse stuck them into my pack.

Nothing had been left in the room across the hall, but the sloppily made bed showed that someone had been in here recently. I flipped the covers back. Nothing except rumpled sheets. I shone my flash under the bed and in the corners but came up empty.

The room overlooked North 2800 Road. I could see the flashes of strobes heralding the arrival of the sheriff’s police. Peppy and I trotted back along the hall, turning off the lights behind us. I went slowly down the stairs so that I didn’t inadvertently touch the railings. Peppy growled as the squad cars reached the drive. I wished there’d been time to explore the attic and the basement, but you can’t have everything.

The flashlight on my cell phone picked up something at the bottom of the stairs, a black shadow. I froze for a second, thinking of the roaches in the kitchen, but when I made myself look, I saw that it was a thumb drive. I slipped it into my jeans pocket and went outside to greet the sheriff.

“So the dog persuaded you to enter,” the sheriff said when we were back in town, in his office. “And you turned on the lights, even at the risk of tampering with the crime scene.”

I had my temper on a lead as tight as the one I’d kept on Peppy. “A rat about as big as your size-thirteens was nibbling on the victim’s nose. It seemed respectful to keep the lights on, not to let the vermin do any more damage than they already had.”