What is the possible relationship between the two speakers?

W: Good Afternoon. May I help you with something?
M: Good Afternoon. [8B] Are you Mrs. Brooks? I received a notice to see you about some books. I’m Richard Crosby…
W: Oh, yes. I recall the name. Won’t you sit down?
M: Thank you. [9D]I just wanted to say that, uh, the missing books. Well, it’s a long story. But I assure you I’m innocent. I can explain everything.
W: [9D]Relax, Mr. Crosby. You’re not under arrest, you know. But I admit I’d like to know why you haven’t returned our books.
M: I nearly returned them, but I forgot, you see, when my wife put the suitcase back in the closet. That’s it.
W: Pardon me? Would you explain that again please?
M: Certainly. I was going to return the books last month. [10C]I put them all in a suitcase. But at the last minute I forgot to take the suitcase to school. Then Harriet put the suitcase back in the closet. After that I forgot all about the books until I received your notice.
W: Well, I’ve never heard that excuse before. So now you’re returning all the books?
M: Yes. Do I have to pay a fine?
W: I’m afraid so. But maybe we can reduce it a little. A story like yours deserves some reward.