Additionally, it appears getting the suspects correct or not has no impact on the mission itself. If you haven't already, it's worth also completing Operation Chaos before you move on to the final set of missions.
Choosing the Suspects\n\n Look at your narrowed down list of suspects from examining the Wristwatch, then eliminate each of the ones who aren't mentioned in the Ledger. Finally look at the gender of the suspects named in the Cassette, and narrow it down to the final set.