Her perfume. [Though the woman's 'attractive' remark does have him looking closer at her. She is his type, decently intelligent, classy, and has a domineering personality.]

It's a rare bottle from southern India. I noticed the empty spot on the owner's wife dresser. Her daughter told me what used to sit there. Now Ms. Swans could have stole it herself, but the girl does not have the intelligence high enough to know how expensive that perfume is. No, the owner gave it to her probably after he killed his wife.