police investigation

I sat up again and was breathing hard, shaking and tasting the bile in my mouth, when Murphy came back out of the room with Carmichael.
“All right, Harry,” Murphy said. “Let’s have it. What do you see happening here?”
I took a moment to collect my thoughts before answering. “They came in. They had some champagne. They danced for a while, made out, over there by the stereo. Then went into the bedroom. They were in there for less than an hour. It hit them when they were getting to the high point.”
“Less than an hour,” Carmichael said. “How do you figure?”
“CD was only an hour and ten long. Figure a few minutes for dancing and drinking, and then they’re in the room. Was the CD playing when they found them?”
“No,” Murphy said.
“Then it hadn’t been set on a loop. I figure they wanted music, just to make things perfect, given the room and all.”
Carmichael grunted, sourly. “Nothing we hadn’t already figured out for ourselves,” he said to Murphy. “He’d better come up with more than this.”

Storm Front Chapter 2, Page 16-17