A bold and very critical witness took the stand on Tuesday in the Christie Scott capital murder trial. Scott is accused of starting the house fire that killed her six-year-old son Mason. Defense attorneys hired John Lentini to testify as an expert in the case. Lentini believes state experts used invalid and unreliable techniques when they determined the fire was deliberately set. According to Lentini, the fire was accidental and started in the television cabinet. During cross examination, Franklin County District Attorney Joey Rushing pointed out that he was not a cause and origin expert. Lentini agreed, saying his job was to determine the credibility of the prosecution's investigation.