[quote=Giant]
"Officer, I know I didn't tell you about the body on the basement, only about the meth!"
[/quote]

Like I said, its a bad excuse but it is still true...
The person who had a body in the basement never lied about it. 
If they had asked him "Ok now is there anything else illegal you have done" and they said "no" then that would be lieing. 
But no-one asked and so no lie was told.