If I were to send a letter of demand in relation to a kidnapping, what do you think you could learn from the individual words in that letter (other than the usage of the word 'I', which is obvious)?
Here's an example:
I have your daughter. If you want her back safe and sound, you will comply with my demands. If you don't, you will never see her again.
You have 24 hours to have 5 million dollars waiting for me at a destination of my choosing. I will contact you in one hour with further details.
If you involve the police or any federal government agent, the only way you'll get your daughter back is in a body bag.