Who Shot Sherlock?

Plot:

Greg is doing his final proficiency test and he has a case to solve. Ironically, he investigates the death of a Sherlock Holmes- wannabe, obsessive to the point of recreating the great detective's living room in his home. He died from a close-range gunshot wound. The murder weapon is not found in the scene although everything other pieces of evidence suggest that it was a suicide. Working under Catherine, Nick and Warrick works on a case of a dead guy found in his car which veered off the highway. Dr. Robbins cannot find the cause of death and it is left to the two detectives to solve the mystery.