"Motive" is an essential element of a number of crimes [ "assault with intent to kill", for enstance].
At the opening of the drama we have not been informed whether Bluebeard has ever been married at all or only a few times, but we feel that he craves companionship, and we know when we hear this "Immer-wieder-heirathen Motiv" (Always About to Marry Again Motive) that he secures it.
The TEASER said, "Jewish Shooter's Motive is a Mystery."
The headline from the LA Times read "Jewish Center Shooter's Motive is a Mystery" despite the fact that his declared motive was contained in the article.
Motive is an important part of proving that a person may have committed a crime, but it should not be confused with intent.