What is the plot summary of "Killings"?

In the story "Killings," Matt and Ruth's son—Frank—has
been murdered by Richard.

Frank was twenty-one and dating
Richard's soon-to-be ex-wife. Richard is known for having a terrible temper.  One night
Richard confronts Frank as he is leaving Mary Ann (Richard's wife), and shoots him twice
not only in front of Mary Ann, but in front of their two
sons.

Richard is released on bail.  Matt and Ruth struggle
deeply with their loss, and with the fact that their son's murderer is allowed to freely
roam around town.

Willis is a friend of Matt's, who owns
several restaurants in town.  When Matt and Willis get together, they agree that they
cannot tolerate what Richard has done, that there are people who commit murder and get
away with it, and they agree that together they will shoot Richard and bury his body
where no one will find it.

The men carry out their plan,
pretending they are helping Richard to leave town in order to start over, however, they
drive over the border into New Hampshire, even while Richard tries to rationalize his
reasons for killing Frank.  They stop in a wooded area, and when Richard tries to run,
Matt shoots him twice, killing him.  They then bury the body and return
home.

When Matt goes into the house, his wife is awake.
 Ruth asks him, point blank, if the did it.  Matt describes the evening, and they agree
that they can never tell their other children.  The story ends as Ruth tries to comfort
Matt.