Luckily or too conveniently, Wu thought. But she moved along. "And Andrew got arrested when?"

"They came by about twelve-thirty, one o'clock. School is out for spring break. And they just took him."

"I was at work," Hal said, "or I would have tried to slow them down, at least."

"Then it's probably better you weren't here." Wu was sitting beyond Linda at the table and could see them both at once. "When did the crimes happen?"

"February." Linda said. "Mid-February."

Wu's face showed her confusion.

"What's the problem?" Hal asked her.

"I guess I don't understand how two months have gone by and all that time, with the police coming by, neither of you thought Andrew was a suspect?"

"He said he didn't do it," Linda said, as though that answered the question. "I know he didn't. He couldn't have."

Ellie came through the door and the conversation stopped while she set out the coffee service. As soon as the door to the kitchen closed back behind her, Wu began again. "Mrs. North, you just said that Andrew couldn't have done these killings. Why not? Do you mean he physically couldn't have done them because, for example, he wasn't there? Does he have an alibi? I mean, beyond the walk he took."

"But he did go for that walk," Linda said. "There's no doubt about that. Besides," she added, "Andrew's just not that kind of person."

Wu's experience was that anyone- if sufficiently motivated- could be driven to kill. And Hal, she'd noticed, had stopped talking, was looking down into his coffee cup. "Mr. North," she said, "why'd they decide just now, after two months, and after they'd talked to Andrew several times? Did something new come up? Do you have any ideas?"