You are going through the belongings of your recently deceased uncle and come upon a small wooden box with the following inscription, presumably describing its contents.
Those who take me, won't know me.
Those who know me, won't want me.
Those who want me, will make me.
Those who make me, will give me away.
You open the box to find it empty. What did your uncle--who was a scoundrel, by the way--keep in this box?
Update: While your uncle was an unsavory person, he was not a murderer.