As Tyler, pick up the bookmark on the desk (DO NOT read the newspaper), and fax it over (the fax machine is near the basketball hoop). Switch back to Carla. Walk to the little office area by the kitchen and get the fax. Put the fax back and sit at the computer next to the fax machine. Choose “Web”, then scroll over to “World” to discover what the bookmark means. Call Tyler back.
At this point, Tommy will come over, so get dressed and go through the scenes with him. Tommy will notice the fax, and tell you what it means. Call Tyler once more, have him find the watermark on the bookmark (get the bookmark back from the fax machine, sit at the desk, turn on the light and look at the bookmark), and say you'll go to the bank yourself (choose “No” when prompted).
Solution taken from PlayStation Trophies:
https://www.playstationtrophies.org/game/indigo-prophecy/tro...