“I can’t recall precisely. I know we agreed that she would come at six to bring the painting, and I don’t remember noticing that she was late at all. I’m afraid I don’t remember when she left. If I had to guess, I would say ten o’clock or shortly thereafter.”

“And she was here that whole time—that is to say, until she left? She did not, for instance, leave and then return?”

“No.” Louisa Wallace looked puzzled. “She came at six with the picture, and then we were together until she left for good. What is this about?”

“Can you confirm that Mrs. Ducane left here no earlier than half past eight?”

“Oh, gracious, yes. She left much later than that. At half past eight we were still at the table.”

“Who is ‘we?’ ”

“Nancy, St. John and me.”

“Your husband, if I were to speak to him, would confirm this?”

“Yes. I hope you’re not suggesting that I’m not telling you the truth, Monsieur Poirot.”

“No, no. Pas du tout.”

“Good,” said Louisa Wallace decisively. She turned back to the picture of herself on the wall. “Color’s her special talent, you know. Oh, she can capture personality in a face, but her greatest strength is her use of color. Look at the way the light falls on my green dress.”

Poirot saw what she meant. The green seemed brighter one moment, then darker the next. There was not one consistent shade. The light seemed to change as one regarded the picture; such was Nancy Ducane’s skill. The portrait depicted Louisa Wallace sitting in a chair, wearing a green low-necked dress, with a blue jug and bowl set behind her on a wooden table. Poirot walked up and down the room, inspecting the picture from different angles and positions.

“I wanted to pay Nancy her usual rate for a portrait, but she wouldn’t hear of it,” said Louisa Wallace. “I’m so lucky to have such a generous friend. You know, I think my husband is a little jealous of it—the painting, I mean. The whole house is full of his pictures—we’ve barely a free wall left. Only his pictures, until this one arrived. He and Nancy have this silly rivalry between them. I take no notice. They’re both brilliant in their different ways.”

So Nancy Ducane had given the painting to Louisa Wallace as a gift, thought Poirot. Did she really want nothing in return, or did she perhaps hope for an alibi? Some loyal friends would be unable to resist if asked to tell one small, harmless lie after being given such a lavish present. Poirot wondered if he ought to tell Louisa Wallace that he was here in connection with a murder case. He had not yet done so.

He was distracted from his train of thought by the sudden appearance of Dorcas the maid, who bounded into the room with an air of urgency and anxiety. “Excuse me, sir!”