Use Batman's Cryptographic Sequencer and track down the XY coordinates 700, 490. You'll intercept a radio frequency that reads these numbers: 9-23-9-12-12-18-5-20-21-18-14-2-1-20-13-1-14 (there will be a buzz sound and repeat these numbers) When matched to the corresponding letters of the alphabet they spell out I WILL RETURN BATMAN.
Locate the coordinates X500.00, Y900.00 on the Cryptographic Sequencer to intercept a radio frequency that contains the following repeating numbers: 5, 15, 9, 7, 21, 18, 18, 14, 3, 5, 24, 15, 12, 7, 22, 3, 10, 5, 15, 9, 22, 3, 8, 25, 26, 15, 16, 25, 10, 15, 17, 25. When decoded, the message reads "YOU WILL PAY FOR WHAT YOU HAVE DONE TO ME".
Using the cryptographic Sequencer, set the coordinates to 200, 500. A voice will speak these numbers: 3-20-26-18-26-16-24-1-11-4-24-9-3-8-5-2-12-18-6-16-7-11-3-10-17-5-13-4-21-8. To decode requires a good amount of work. First, set each number to a letter in the alphabet but in reverse so that Z=1, Y=2, X=3 and so on. From there you use a special cipher known as a Vigenere Cipher that requires a keyword to translate. By using the keyword "scarecrow", the message translates to "FEAR WILL TEAR GOTHAM CITY TO SHREDS". Since the keyword is scarecrow, it is likely that Scarecrow is behind this message and possibly more.