An old man sends his son, who is in prison, a letter.
Charlie promptly sent a letter home to his old man.
The next day armed police swoop down on the old mans house.
The old man is bundled away to his alotment, and waits while the police dig up every inch off the ground looking for bodies and cash.
After a couple of hours digging without a single body or pound coin bering found, the disgusted inspector calls of the search and the police leave.
The next day the old man gets another letter.