The Poison Tree — Tony Strong

The handsome student who lived at 57 West Street died there too, his brutal murderer never brought to justice.  For Terry Williams, returning to Oxford University to complete a doctorate in detective fiction, the house's macabre history simply means it's cheap.  She never suspected the twisted passsions that led to the student's death would entwine around her own life.

A stray cat traumatized by some past act of cruelty, a hidden cache of pornography, a close neighbor's illicit love affair .  .  .  soon Terry is drawn into a mystery more chilling than any in her fictional studies.  And back in the classroom she is uncovering a secret, erotic side to academia, where moral rules are suspended and where a tragic obsession may prove deadly for the innocent .  .  .  or for a woman seeing too clearly into a killer's dark and merciless heart.