I will be able to post CSI spoilers much further in advance in the future but it has taken me some time to get caught up. Please let me know if you want future CSI spoilers as detailed as this. Due to the nature of CSI, things are very detailed and it is possible sometime to know how the entire episode will go. I'll do a more condensed version that does not give the mystery conclusion away if more people prefer that.
This episode will air March 30, 2006.
There is a trial going on about a young man, Marlon, accused of murdering a teenage girl named Christy. At the trial Marlon's sister Hannah confesses to the murder. The problem is now that both Marlon and Hannah have confessed and the CSIs are brought in to determine which one of them is lying.
During the course of the investigation we learn that Hannah is a genius with an IQ of over 170. Hannah is very academically gifted and even conducts her own science experiments. Hannah says that she murdered Christy because she was being bullied and Christy always played tricks on her. Christy died because sodium was put in her shower head at school and once water was turned on the shower head exploded. Hannah says that this was her way of getting back at Christy. Hannah says that her brother Marlon was just trying to protect her and that is why he confessed.
Over the course of the investigation, the evidence begins pointing to Hannah. She won an award for the sodium experiment at a science fair and had access to sodium at the school's lab. Hannah also used her computer to print "out of order" flyers from the school's printer to hang on the bathroom door to make sure that nobody would foil her plan.
In the meantime, the CSIs find a bloody fingerprint from Christy's boyfriend Scott in Christy's car. The CSIs think that Hannah is now just covering up for Scott because she had a crush on him. Scott defends himself by saying that the blood was from when he took Christy's virginity and the lab goes to analyze the fingerprint for lubricants and such. Turns out Scott was telling the truth and now they are back to figuring out if it was Hannah or Marlon who killed Christy.
The CSIs think they are on to something when they find sodium in Hannah's bathroom but then discover that she shares it with Marlon. Then the CSIs go to the high school to walk though the crime. Hannah would not have been tall enough to put the sodium in the shower head but Marlon would have. But then they find a chair in the next shower stall over that is mainly used for hanicap use. Hannah could have used the chair to stand on. Then comes the task of moving the body on to the football field. The CSIs determine that Hannah could not have moved the body on her own so Marlon must have had to be the one to carry the body. The CSIs confront Hannah with this information and she says she used the landscaper's cart to move it.
Now we are at the conclusion of the trial and Marlon is found not guilty due to reasonable doubt that Hannah cast on the case. The CSIs ask the D.A. if they are going to go forward with prosecuting Hannah and the D.A. says no because she would get off for the same reasonable doubt. Hannah was smart enough to skew the evidence so that the CSIs could not figure out which one committed the murder and essence they both get off for it.