There was no good case because, as the article explains in quite a lot of detail, the team was instructed not to interview anyone in any position of responsibil

There was no good case because, as the article explains in quite a lot of detail, the team was instructed not to interview anyone in any position of responsibility at Goldman/Paulson. It also explains, in quite a lot of detail again, how Goldman was not simply "assembling a security of mortgage bonds." There was quite likely intentional fraud involved.