Another oldie but moldy.
The President of the United States is looking out the window of the oval office one winter morning.
He sees, written in the snow, in urine, the words "you stink"
The POTUS calls in the USSS and the FBI for a full investigation
The Director of the FBI reports, "Mr. President, I have some good news and some bad news"
"Ok, what's the good news?"
"Mr. President, we have analyzed the chemical composition of the urine and our analysis indicates it belongs to the Vice President"
"Wow, so what's the bad news?"
"Sir, it is your wife's handwriting"