A new variant of the CIA porn investigation emails are now putting the extortion payment instructions in password protected PDF attachments. These scam emails pretend to be from a CIA technical collection offer who states that your name is part of an investigation into underage pornography. For a fee, they would be willing to wipe your information from the case files. Included in the email is the password for the attached PDF file. Once the password is entered, the PDF will open and display instructions to send $5,000 USD to the enclosed bitcoin address.
Source: https://www.bleepingcomputer.com/news/security/cia-porn-extortion-scams-now-use-password-protected-pdfs/