The question of the dead mistress
(Book)

"Mrs. Washburn takes on the case of a woman who thinks her husband has a ghost mistress, but Samuel's Asperger's traits mean he does not believe in ghosts"--,Provided by publisher.

"Is my husband having an affair with a dead woman?" For Samuel Hoenig, the proprietor of a unique agency called Questions Answered, the answer to this most recent question is simple. Since there's absolutely no evidence that apparitions exist, it would be impossible for Ginny Fontaine's husband to be having an affair with one. But Samuel's associate, Janet Washburn, isn't so easily convinced. Wrestling with his complicated feelings for Ms. Washburn, Samuel proposes that she take the lead on the question. As soon as her research begins, the husband in question ends up dead, leaving Janet and Samuel wondering if they stand a ghost of a chance at unraveling this twisted tale of danger and deceit. -- from Amazon.