mr. al-nashiri, because they want to introduce circumstances of torture to primari primarily stave off anxecution. >> if the judge wants to exclude hearsay statements, the evidence is going to whittle down to very little. if the judge allows in those statements that will be very important to know for future cases. >> reporter: if i were the defense attorneys i would be looking at how the prosecution conducts itself, and what themes the prosecution hits. if i were the prosecutor, i would be watching what sorts of evidence are excluded, and what sorts of evidence are admitted because those are open questions, and al-nashiri's trial is probably going to answer some of those questions. >> reporter: the hope is once this trial and others start, the american public will get a far better understanding of what happened during these attacks. >>> six world powers and iran beginning a second day of talks in vienna today. they are trying to negotiate a comprehensive solution to iran's nuclear program. the talks could in time produce a settlement. senior iranian firms said they were pretty for long an