“That is correct.” A sigh accompanied Agemaki’s response.

“My investigation has uncovered facts that cast doubt on your story,” Sano said. “Is there anything that you forgot to mention-or that you’d like to change?”

He was certain that the murder hadn’t gone unnoticed by everybody except the killer. The thin walls of the private chambers, and the proximity of Makino’s room to the others, made it likely that someone else who’d been there that night had witnessed something. Someone, perhaps not just the killer, was withholding information, and it could be Agemaki.

“If so, now is the time to tell me,” Sano said. “I’d be more inclined to excuse a mistake than I might be later.”

Agemaki hesitated for an almost imperceptible instant before she murmured, “There is nothing else. I cannot alter the truth.”

Her hesitation spoke more truth to Sano than did her words. Now he knew she was hiding something. Yet people had other reasons to keep secrets besides being guilty of a crime. Those reasons included the desire to protect someone else.

“What are your feelings toward your husband’s concubine?” Sano said.

She gave him a sidelong glance from beneath lowered eyelashes. He thought he saw a glimmer of confusion cross her face. “Okitsu-san is like a little sister to me. We are the best of friends.”

Sano wondered how often a wife felt kindly toward her husband’s beautiful young concubine. “You didn’t care that Okitsu had won Senior Elder Makino’s affections?”

“Not at all.”

She wisely kept her response brief; if she felt any compulsion to protest too much or explain herself, she resisted it. But Sano wondered if Agemaki was more likely to have killed to protect her future from Okitsu than to have lied to protect Okitsu from the law.

“What about the actor Koheiji and your husband’s chief retainer?” said Sano. “Are you also friends with them?”

“No.”

A single word could convey many shades of meaning, Sano observed. In Agemaki’s reply he’d heard scorn for the idea that a lady of her rank would be friends with a hired entertainer or a family vassal. She wouldn’t have lied to protect them, either. If she’d withheld compromising information about Makino’s death, she aimed to protect herself.

The troops stirred, restless; Detectives Marume and Fukida watched Sano, ready to defend him if need be. Ibe and Otani gestured for Sano to speed up the interrogation.

“Yesterday you told me that your family is in service to Lord Torii,” said Sano. “But in fact, your father was a wandering rōnin. Your mother was an attendant at Asakusa Jinja Shrine, and so were you. Isn’t that true?”

He saw Agemaki’s throat contract as she swallowed: He’d shaken her composure. But she said calmly, “My father was a samurai retainer to the Torii clan.”

“Your friends at the shrine say not.”

Her gaze briefly touched his; pride flashed like a torn banner in her eyes. “I know better than they do.”

“Very well.” Sano understood that her background was her vulnerable spot. That he’d exposed it might open her up to more revelations. He strode closer to her. “You were a prostitute, a woman of uncertain parentage and few prospects.”

Agemaki flinched at the words as though he’d flung nightsoil on her expensive robes. Sano knew of other women in her position who liked to forget the past and pretend that their existences as wives of rich, powerful men were the only lives they’d ever known. He hoped he was tormenting a criminal, not an innocent victim.

“Senior Elder Makino brought you to his house… as his concubine. He was still married to his first wife then, wasn’t he?” Sano said.

“Yes.” Involuntary movement shifted Agemaki’s body.

“What happened to his first wife?”

“She died,” Agemaki whispered.

“How did she die?”

“From a fever.”

“According to the Edo Castle physician, you nursed her when she took ill,” Sano said, bringing into play the information Hirata had given him.

“She wanted me to take care of her.” As self-defensiveness overrode her feminine reticence, Agemaki explained, “She wouldn’t let anyone else. She trusted my healing skills.”

“But she got worse instead of better,” Sano said.

He watched Agemaki twist and rub her hands together, as if washing them. He was interested that she seemed more upset now than while discussing Makino’s murder. She must have been prepared for questions about his death but not his first wife’s or her own past. Maybe she’d not expected the subjects to come up. A person’s ability to dissemble stretched only so far.

“I did my best to save her,” Agemaki said, “but she was too ill.”

“According to the Edo Castle physician, you were the one who mixed her medicines,” Sano said. “You fed them to her. What did you put in them besides healing herbs?”

“Nothing!” Agemaki’s head came up; her eyes glittered.

“Did you poison her?” Sano said.

“I didn’t!” Panic crumbled Agemaki’s sedate mien. The guise of the demure, grieving widow deserted her. “It wasn’t my fault that she died! Anyone who says otherwise is lying!”

Sano wished he could tell whether she’d killed Makino’s first wife and feared due punishment, or if she was panicking because she was innocent and wrongfully accused. He’d seen similar reactions from guilty as well as innocent people.

“You gained by the death of Makino’s first wife,” Sano reminded Agemaki. “Makino married you. But then he took a new concubine. History repeats itself. You knew that Okitsu could replace you just as you’d replaced his first wife. Did you kill him to prevent him from divorcing you, marrying Okitsu, and cutting off your inheritance?”

Agemaki relaxed her body, stilled her hands, and spread a mask of false serenity across her features. “I did not.”

“Lord Matsudaira’s nephew, Daiemon, was in this estate the night your husband was murdered,” Sano said. “Did you see him?”

“No. If he was here, he must have come while I was asleep.”

“You’re not investigating Daiemon,” Otani said with a dark frown at Sano. “No more questions about him.”

“While you were asleep, or while you were beating your husband to death?” Sano said, ignoring Otani. “Did he catch you in the act?”

“Careful, sōsakan-sama,” said Ibe.

Agemaki repeated quietly, “I didn’t see him. I did nothing for him to see.

“Last night Daiemon was stabbed to death in a house of assignation,” Sano said even as the watchdogs glared at him. “What were you doing then?”

“I went out for a ride in my palanquin.” Agemaki seemed indifferent to the news of Daiemon’s death.

“Where did you go?” Sano said.

“Nowhere in particular. Just around town.”

“Enough of this,” Ibe told Sano.

Sano nodded. He’d learned what he’d wanted to know. Agemaki had been in the city last night. Perhaps she was Daiemon’s missing paramour-and killer.

“I’m satisfied that she killed Makino’s first wife,” Ibe said.

“And Makino as well,” Otani said. "Once a murderer, twice a murderer.”

“Go ahead and arrest her,” Ibe told Sano. “If you’re so anxious to solve Daiemon’s murder, let her take the blame for that, too.”

Agemaki sat frozen between the watchdogs, like a cat who thinks that if she doesn’t move, predators won’t notice or attack her.

Sano said, “The evidence against her is indirect. It’s not sufficient for me.”

“It’s sufficient to convict her in the Court of Justice,” Ibe said.

Sano knew that for a fact, but he also knew that virtually all trials in the Tokugawa justice system resulted in conviction, even if the defendant was innocent. Agemaki might be guilty of multiple murders-or not. He was by no means certain which. Even while the watchdogs held his son hostage, Sano refused to let them rush him into a faulty decision.

“You gave me a choice of two suspects,” he told them. “I’ll interrogate Okitsu before arresting anyone.”