“Possible, but probable?” Alex’s expression remained dubious. As he had stated, blood was nearly impossible to remove 100 percent. Hence, criminalists could build entire careers using blood evidence to catch savvy killers who’d bleached walls but forgotten the window latch, or loofahed off a layer of their own skin but forgot about the wind-up dial of their watch. Killers could clean only what they could see. While thanks to tools such as high-intensity lights and chemicals such as luminol, a savvy investigator essentially approached every scene with X-ray vision.

D.D. was struck by a fresh thought. “Let’s consider this from another angle. We have a killer who not only entered undetected but also left that way. Except on the way out, he should’ve appeared disheveled, even bloody from all the knife work. So how did he disguise all that?”

Alex shrugged. “Most obvious solution would be for him to shower after the killing, as you suggested. He washed off all traces of blood, changed into fresh clothes, then walked out the front door, just another guy in the neighborhood.”

“Except, as you said, we’d see traces of blood leading from the bed to the bathroom, not to mention on the bathroom floor, shower, sink. Meaning . . . What if he was naked? What if, after subduing his victim . . . before getting started with the main event, the killer removed his own clothes?”

“Prudent,” Alex said. “Blood is easier to remove from skin than clothes.”

“Other thing I’m noticing is that there don’t seem to be any towels missing from the victim’s bathroom. There’s a hand towel in the hand towel ring, and two bath towels on the rack. So if he showered here, what did he use to dry off?”

Alex nodded shortly, considering.

“Maybe,” D.D. continued, “as long as the killer is bringing in props for the murder, he’s also providing his own cleanup kit. Packed a couple of towels, maybe even his own bath mat, for the floor next to the bed. See this mark here?” She gestured to the lone smear pattern, near the right-side nightstand. “He lays down the bath mat, strips off his clothes, then climbs on the bed to do what he’s going to do. Afterward, he steps from the bed back onto the bath mat, wipes himself down with his towel, replaces his clean clothes, socks, shoes. Then it’s a simple matter of rolling up the mat, bloody towel, knife, etcetera, tucked safely inside. Sticks everything back in his duffel bag and he’s good to go. Certainly that would explain the lack of blood evidence in the rest of the house, including the bathroom.”

“Not just prudent,” Alex amended. “Clever.”

“Experienced,” D.D. emphasized. “Isn’t that what the ME said? This guy knows what he’s doing. And he’s controlled. From the beginning through the middle to the end. We’re not going to find any magic answers here.”