Inspector Logan

 As you can know from book title, the main character named "Jenny Logan" and her job is a "Inspector".
 In Edinburgh of Scotland, one missing incident occurred. A woman named "Margaret Kerr" was lost and her husband come to police office.Then He told clear about incident.
Logan said to him 'your wife isn't child' and she have to start a seach.

While seaching, Margaret was found dead.
Who is the criminal?!
If you want to know, please read it.