Coyle sat upright in his chair and massaged his neck. He was alone in the dark Violent Crime room, the only light coming from the two laptop monitors in front of him. By now, he had been sitting in the same spot for twelve hours, with just a break at six for an Arby’s melt. Tired as he was, he also felt inside a zone of concentration. For the past hour, his earbud had been playing a mix of Irish rock—Thin Lizzy and, after that, the Boomtown Rats—and he had been eating jalapeño-flavored trail mix that had orange-powdered his fingers and the keyboards.

He read the paragraph on the Mercedes website for the third time. It described how the so-called “Ponton” sedan, like the one in the Spring Lake Park surveillance film, had been manufactured from 1953 to 1962. Year to year, the main differences were in engine size, not body design.

Coyle had loaded a photo of the car from the surveillance video on a second laptop, and now he panned slowly across the image. The trunk shape and taillights were clearly the Ponton style, but the car might be from any of nine years. The color could be dark blue, green, or even black.

He toggled from the Mercedes website to the Department of Motor Vehicles database. More than two hundred owners of Mercedes models dated 1953 to 1962 were registered in California.

Coyle stared at the spreadsheet. Who were these people, and why did they want these dumpy-looking cars? He clicked on 1959 at random and scanned down the alphabetical list of names: Marilyn Aldrich, Kenneth Ashby, Steve Baab. One of them, he thought, is the owner of the car that drove through the Violetti Gate and deposited the body of Jane Doe.

An alarm on the right-hand laptop suddenly beeped, and Coyle jumped at the sound. He had set the alarm to go off every thirty minutes to remind him of the time.

Coyle felt some satisfaction in his progress. A two-dimensional plot analysis of the hooded man in the video, using known heights of other objects in the surveillance film, indicated the man was about five feet, four inches. Based on the way the hooded figure disconnected the gate lock, the man also appeared to be left-handed.

The scarf that the search dog found in the park turned out not to be a woman’s—surprising to Coyle—but a brand sold in the men’s department of a chain store. The label indicated it was a Sheer Danger brand, with an Ardent Autumn design, and in stock in six Northern California outlets. Coyle had a note to check with Mahler to see if he wanted to pursue trying to get a court order to track barcode sales.