Growing Potatoes

A farmer writes to his son in prison, "I can't grow potatoes this year. I'm too old to be digging up the field."

Soon he gets a letter back from his son, "You can't dig in the field, that's where I buried the bodies!"

The next morning, police officers arrive and dig up the entire field but find nothing.

Soon the farmer gets another letter from his son, "Now, Dad, you can grow potatoes. It was the best I could do from here."