Why is Floyd Wells concerned when he hears the news of the Clutter murders?
He knows that he was partly responsible for their murders, though unintentionally.

How does fate come up again in Floyd's encounter?
The investigators would have gotten to him a few days after he went to share his information anyway, since they were tracking down all of the Clutters' former employees/hired workers.
Why doesn't Floyd want to tell his story to the KBI?
He doesn't want to get in trouble and is afraid of how he will be treated in prison if he shares information (like how a kid is treated by classmates after "tattle-taling").
How does Marie, Dewey's wife, react when she sees pictures of Dick and Perry?
At first she is excited for Dewey, but then wishes Dewey hadn't shown her because she finds the pictures frightening. She recognizes the anger in Dick's eyes.
How do the Hickocks feel about their son? In what way do they "cover" for their son? In what ways do they recognize and admit his mistakes?
They say he was just going on a trip and was a good man except for some mistakes, which were "only because of his accident.

" They also blame it on "that friend of his." However they say they hope he gets found and recognize that his previous crimes were unacceptable (they have no clue their son was involved in murder).

How do the views about Dick differ between the community and his family?
The community only sees his parents as respectable, while Dick's parents see both themselves and their boy as respectable. The community views Dick as the troublemaker, while his family mostly views him as the victim.
Why do you think the agent does not mention the murders in talking with Dick's parents?
It will be easier to get honest information about them and be welcomed in by them, and he is still piecing the facts together.
What is the Hickocks's impression of Perry? Why is this ironic?
They view him as the violent and aggressive instigator, while the one who more fits that description is actually their own son.