Or said another way, "It's the seriousness of the charge, not the nature of the evidence."
Investigate and if no one committed a crime, no one goes to prison. If someone committed a crime, they will go to prison.
http://townhall.com/columnists/emmetttyrrell/2011/07/14/the_kultursmog_against_murdoch/page/full/
Emmett Tyrrell
The Kultursmog Against Murdoch
Anyone encouraging the government of the United States to investigate a news organization without proper cause is an enemy of freedom. And the harassment of Rupert Murdoch is being executed by enemies of free speech.