Student or Learner
"Marc Piron seemed more straightforward. Comes to Australia, sees business opportunity, meets Fiona, falls for her and decides to stay...But Still these two seemed like cardboard cut-outs to the investigator.
(Someone gathers facts about Marc and Fiona to the investigator. But the investigator "still didn't have a picture of the people in his head." )
So, what does that mean by saying people are like cardboard cut-outs in the context?
Thanks a lot.