Sorted on book title (not in series order)

Petra Hammesfahr

The Sinner

Cora Bender killed a man. But why? What could have caused this quiet, lovable young mother to stab a stranger in the throat, again and again, until she was pulled off his body? For the local police it was an open-and-shut case. Cora confessed; there was no shortage of proof or witnesses....Read more

The Sinner, Petra Hammesfahr

As you can tell from the blurb, THE SINNER is a whydunnit, as opposed to a whodunnit book, although that's way too simplistic a description.  When Cora Bender stabs a man to death in front of family, friends, and a crowded park, nobody realises that she was originally planning to commit...Read more