Why chris benoit killed family and himself?

OMG thank you borken dreams i thought i was the only one who thought that. I turn on raw and i see chris benoit dies- the next day every single news channel says he killed himself because he was on steroids! the autopsy showed no signs of steroids in hid body. They didn't DNA check anything, they just made up a story and went with it- it was pretty stupid there's no hard evidence that he did it....