Ballou motioned them over to the machine. “Toss in a quarter.”

Petra did. He took her hand and cupped it below the spout. Turned the handle and little balls tumbled out and her nose filled with the aroma of ripe seafood.

“Feed ’em,” said Ballou. “It’s fun.”

“Which pond?”

“That one. They’re babies, need the nutrition.” Motioning toward the first pond, where the little fish were still clamoring. Petra walked over and tossed in the pellets and a finned riot ensued.

Isaac was already three ponds ahead. Bending low and examining the fish that had risen to greet him. Larger ones, red and black and gold and blue.

He said, “Mr. Ballou, do you use domestic stock or are these from Niigata?”

Ballou lowered his gaze and stared at the kid. “You know koi.”

“I’ve admired them,” said Isaac. “My mother’s employers have a pond.”

“Admire them, huh?” said Ballou. “Then get into it yourself.”

Isaac laughed.

“Something funny, son?”

“It’s a bit beyond my budget. And space. I live in an apartment.”

“Hmm,” said Ballou, “then get yourself a good job, work your tail off, and buy a house. Pay down the mortgage a bit and reward yourself with a Japanese garden and a pond full of nishikigoi. Nothing like ’em to lower your blood pressure.”

Isaac nodded.

“You do all that, son, come back and buy some fish from me and I’ll give you a free karasu- that’s the black one. Symbol of good luck.”

Petra said, “I could use some luck. On Marta Doebbler.”

Ballou said, “Here we were talking about pleasant things… you drink tea?”

Back in his kitchen, he poured steaming green liquid into three stoneware cups.

“Don’t think I’m some fanatic. Asian culture soothes me. When I got out of rehab a koi dealer, a nice old man in Gardena, hired me to mop up his place. I mopped for two years, kept my mouth shut, started asking questions by the third year, learned a bit. He died and put me in his will. Left me some of his breeding stock. That motivated me to buy this place, set up a little weekend business. It’s real peaceful. I don’t think about my other job with fondness.”

Petra sipped the hot, aromatic tea.

“Marta Doebbler’s a good example,” said Ballou. “Ugly scene. When I think of the things I got used to working Homicide.” He placed a thumb under his suspenders, gazed absently through the window. Then back at Isaac.

“You seem like a nice kid. Why would you wanna do this to yourself?”

Petra said, “Isaac’s going to be a doctor. Meanwhile he’s getting a Ph.D. in biostatistics.”

“Meanwhile?” said Ballou, appraising Isaac all over again. “We’re talking Einstein?”

Isaac muttered, “Hardly.” Flushed clear through his nutmeg complexion. Pink as medium-rare beef.

Petra said, “Can we talk about Doebbler?”

What I remember,” said Conrad Ballou, “was that the husband was interesting.”

He returned to his tea, gave no indication of having more to say.

Petra said, “Interesting as in prime suspect?”

The old guy nodded. “There was no evidence tying him to it. Everyone said him and the vic were getting along fine. But I liked him for it.”

He put his cup down. “His reaction to his wife’s death was off. Stone-face, not a tear. When I did the notification call, I brought a pocket full of tissues, like I always did. Didn’t end up using one. Doebbler just stood there, with this flat look in his eyes. Sometimes that happens before they fall apart, I kept waiting. He just stood there staring. For a second I thought he’d gone into one of those whatchamacallit seizures. Then he says, ‘I guess you’d better come in.’ ”

“Guy’s an engineer,” said Petra.

“So what?”

“It doesn’t explain it but sometimes that type…” Remembering her days as a faculty brat. Dr. Kenneth Connor, professor of anthropology at the University of Arizona, Tucson, squiring his little daughter to academic soirees. Meeting the tenured crowd. Finding most of them regular folk with slightly higher I.Q.s, a few crashing bores. A few really reprehensible jerks.

“The type?” said Ballou.

“Engineers, physicists, mathematicians, all those megabrains. Sometimes they don’t react emotionally the way the rest of us do.”

Ballou glanced at Isaac, as if wanting confirmation straight from the source. Isaac pushed a smile onto his lips.

Ballou said, “Well, Doebbler was a kind of rocket scientist, I guess. Worked over at Pacific Dynamics, electronics stuff, some sort of computer job.”

“Anything else besides his demeanor make you suspect him?”

“She was called out of the theater. It had to be someone familiar with her schedule, who else would know where she was? And who else could’ve gotten her to leave the theater without telling her friends where she was going.”

“The husband claiming an emergency,” said Petra. “Maybe about the daughter.”

“That would’ve brought her out,” Ballou agreed. “The kid was Doebbler’s alibi. He’d been home with her all night, Marta was having a girl’s night out. I talked to the three friends she went with. No one had anything juicy to offer about Marta’s private life, but when I pressed them I could tell they didn’t like Kurt. One even said she thought he’d done it.”

That hadn’t been in the murder book.

Petra said, “That’s pretty strong.”

“She didn’t like him. No one seemed to.”

“How’d he and Marta meet?”

“Germany. She was a brain, too, studying astronomy. He was a foreign exchange student. After they got married, she dropped out and became a full-time mom.”

“That could be frustrating.”

“Sure, that’s what I thought,” said Ballou. “Maybe she tried to reduce her frustration the old-fashioned way. But if she was having an affair, I never found evidence of it.”

Petra said, “Did you talk to the daughter?”

“Poor little thing, didn’t want to pressure her.” Ballou tugged at his mustache. “She sure reacted, crying all over the place. You’d think Doebbler would’ve tried to comfort her. All he did was offer her juice.”

“Juice?”

“A glass of orange juice: ‘Here, drink, you’ll feel better.’ Like vitamin C would help with losing her mother.” Ballou emitted a dry, hoarse laugh. “I would’ve loved to make him for it… how come you’re reopening it?”

“It may be related to some others.”

“Others you suspect Doebbler did?”

“Others with some similar forensics.”

Long silence. You could hear the burbling of the fish ponds, here in the kitchen. Then a loud splash.

“Spawning season,” said Ballou. “They jump. Sometimes they jump clear out of the pond and if I don’t get there in time, I’ve got a dead fish.”

He got up, peered out the window. Sat back down. “So far, so good. You want to tell me about these others?”

“Five other brainings,” said Petra. “Yearly intervals. All on June 28.”

Ballou gawked. “You’re putting me on.”

“Wish I was.”

“Before Marta?”

“All after Marta. From what we can tell, she was the first. If it’s a series.”

“If?” said Ballou. “All on the same day? That sounds pretty convincing.”

“But the victims are all over the place in terms of sex, age, and race.” She gave him a few details.

“See what you mean. Still… so, how’d you discover this? Department finally doing something about working cold ones?”

“Mr. Gomez, here, found them.”

Ballou studied Isaac, yet again. “Did you?”

“By accident,” said Isaac.

“Bullshit. I don’t believe in accidents. My smashing into a building was no accident. It was stupidity. And your finding all this out wasn’t an accident, it was smarts.” He leaned over suddenly, clapped the kid on the shoulder. “You’re definitely going to deserve a pond one day- a big one. You’re going to afford it and you’re going to build it and I’m going to stock you with beauties.”