A man was found dead by a gunshot wound in his study at home.
He lay slumped over a desk, with a gun in his grip.
On the desk stood a tape recorder.
The detective pushed the play button:
"I cannot continue living anymore. I have no raison d'être,"
said the message, which was immediately followed by the sound of a gunshot.
As soon as the detective heard the message, he knew it wasn't a suicide but a murder.