Well Duh

http://www.nytimes.com/2008/02/14/nyregion/14slay.html?scp=2&sq=psychiatrist%20stabbing&st=nyt

So while I was waiting for my lunch to heat up -Microwavable as usual - i saw the above linked article in the NY Times.

For those of you who are like me and won't take the time to click the link, here's a summary:
Late at night two psychiatrists are working in their office. A man comes in and asks to see one of them. He's busy with another patient. So, the man sits, makes small talk and then goes into the other psychiatrist’s office instead. While in there he cracks and stabs the woman to death. Meanwhile the other psychiatrist has heard the screams of his colleague and rushes in - so he then gets stabbed.

Where's the well duh part? Here it comes my friends, "A day later, the police said they did not know the motive for the frenzied attack ..."

DUH - why can't we just say because the killer was CRAZY! When did we complicate things so much that we have ruled out the obvious?