I went to the reference department. My personal table had been rudely preempted by someone other than me so I settled at another table. I dumped my bag in the chair and then crossed to the section where the Polk and Haines directories were shelved. I pulled volumes for 1966 and 1967, then loaded the city directories for the same years on top. I added the current telephone book and carried the stack to the table. I sat down and arranged the references in front of me, keeping them in easy reach while I leafed through the Thomas Guide to the pages devoted to Horton Ravine. I looked up the name Corso in both the Polk and the Haines for 1966 and 1967. There was only one Corso listed, that being Lionel M. on Ocean Way. I made a note of the address and then checked the current telephone book. Lionel Corso was still listed at that address. I was under the impression he’d died. I had a dim recollection of running across his name in the obits, but it was possible his widow, if he had one, still owned the house.

I looked up Walter McNally’s old address in the same two crisscross directories. In 1967 McNally senior had owned a home on Bergstrom Hill, just outside Horton Ravine and connected by a street called Crescent Road, in easy range of the Corsos’ place. Walter must have sold the family home when he moved to Number 17 Juniper Lane in the Valley Oaks Senior Settlement. I pulled out a pencil and made discreet black dots in the Thomas Guide, designating the 1967 addresses for the Kirkendalls on Ramona Road, the Unruhs on Alita Lane, the Fitzhughs on Via Dulcinea, the McNallys on Bergstrom Hill Road, and the Corsos on Ocean. I didn’t care about the Suttons, who’d lived on the western edge of the Ravine. On the day in question, Michael had been dropped off at the Kirkendalls’, whose lot touched the Unruhs’ at the bottom of the hill.

I returned the reference materials to the shelves, and left the library and drove into Horton Ravine to the Home Owner’s Association. There I appealed to the two kind women working in the office, who gave me a dandy map of all the bridle trails through the Ravine. I sat in my car, map open and propped up against the steering wheel, while I studied the warren of trails linking the properties of all the principals. If I affixed the trail map to the wall and used a pushpin for each of the relevant locations, a string running around the lot of them would form a crude circle.

Now all I had to do was persuade Cheney Phillips I was on the right track. I went back to the office and called.

“Lieutenant Phillips.”

“Hey, Cheney. This is Kinsey. Are you tied up at the moment?”

“I’m here at my desk for another twenty minutes. What’s up?”