What is the most important part of a mystery or thriller to each member of the group?

Is it the character development, plot, action, or dialogue that moves the story forward?

How would you rate the book in these areas?

What motivated the serial killer to these horrific acts of violence?

Was the motivation convincing in regards to the crime and why?

How effective is the author’s use of plot twists and red herrings?

Were you able to predict things before they happened, or did the author keeping you guessing until the end?