you remember him, he says numbers seven and eleven had similar injuries, injuries that stood out if compared with those of the others.

“Another thing I just remembered is the makeup. After Church was dead they found the makeup in the Hyperion apartment, remember? They matched it to nine of the victims. The two victims there was no makeup for were—”

“Seven and eleven.”

“Right. So what we have are multiple ties between these two cases—seven and eleven. Then you have a tangential connection to number twelve, this week's victim, based on the pimp recognizing the customer's voice. The connection gets stronger if you look at the lifestyles of the three women. All were in porno, all worked outcall.”

“I see the pattern within the pattern,” Locke said.

“Gets better. Now, we add in our lone survivor, she was also in porno and did outcall work.”

“And she described an attacker who looked nothing like Church.”

“Exactly. That's because I don't think it was Church. I think the three, plus the survivor, make up one set of victims of one killer. The remaining nine are another set with another killer. Church.”

Locke got up and began pacing back and forth on one side of the dining room table. He kept his hand to his chin.

“Anything else?”

Bosch opened one of the binders and took out the map and a folded piece of paper on which he had earlier written a series of dates. He carefully unfolded the map and spread it on the table. He leaned in and over it.

“Okay, look. Let's call the nine Group A and the three Group B. On the map I have circled the locations where Group A victims were found. You see, if you take the Group B victims out of the picture, you have a nice geographic concentration. Group B vics were found in Malibu, West Hollywood, South Hollywood. But the A list was concentrated here in eastern Hollywood and Silverlake.”

Bosch ran his finger in a circle on the map, showing the dumping zone Church had used.

“And here in almost the center of this zone is Hyperion Street—Church's killing pad.”

He straightened up and dropped the folded paper on the map.

“Now here is a list of dates of the eleven killings originally attributed to Church. You see there is an interval pattern at the start—thirty days, thirty-two days, twenty-eight, thirty-one, thirty-one. But then the pattern goes to hell. Remember that? How it confused us back then?

“Yes, I do.”

“We have twelve days, then sixteen, then twenty-seven, thirty and eleven. The pattern disintegrates into no pattern. But now separate the dates of Group A and Group B.”

Bosch unfolded the paper. There were two columns of dates. Locke leaned over the table into the light to study the columns. Bosch could see a thin line, a scar, on the top of his bald and freckled crown.

“On Group A we now have a pattern,” Bosch continued. “A clearly discernible pattern of intervals. We have thirty days, thirty-two, twenty-eight, thirty-one, thirty-one, twenty-eight, twenty-seven and thirty. On Group B we have eighty-four days between the two killings.”

“Better stress management.”

“What?”

“The intervals between the acting out of these fantasies is dictated by the buildup of stress. I testified about this. The better the actor handles it, the longer the interval between killings. The second killer has better stress management. Or, at least, had it back then.”

Bosch watched him pace the room. He took out a cigarette and lit it. Locke said nothing.

“What I want to know is, is this possible?” Bosch asked. “I mean, is there any precedent for this that you know of?”

“Of course, it's possible. The black heart does not beat alone. You don't even have to look outside the boundaries of your own jurisdiction to find ample evidence it is possible. Look at the Hillside Stranglers. There was even a book written about them called Two of a Kind.

“Look at the similarities in the method of operation employed by the Nightstalker and the Sunset Strip Strangler in the early eighties. The short answer is, yes, it's possible.”

“I know about those cases but this is different. I worked some of those and I know this is different. The Hillside Stranglers worked together. They were cousins. The other two were similar but there were major differences. Here, someone came along and copied the other exactly. So closely that we missed it and he got away.”

“Two killers working independently of each other but using exactly the same methodology.”

“Right.”

“Again, I say anything is possible. Another example: remember in the eighties there was