Grissom's case was interesting specially with the cause of death. A piece of lead accumulated over years of eating chocolate is bizarre, but is it possible? Even when Sara has been a CSI for 3 years now, she looks and sounds like a trainee, even asking more questions than Greg, who's only a lab technician. Not only in this episode but in probably the first half of the season. I guess her attitude didn't help a lot in her first years.
Nick seems to progress more quickly than Sara and Catherine is a good teacher. Unfortunately here they had to deal with what seems to be normal people with cold hearts.