A crime scene sketch is a simple line drawing used by investigators to document the layout and details of a crime scene. It depicts the positions of items like doors, windows, stairs, weapons, blood stains and other evidence. A rough sketch is prepared at the scene with measurements and a legend explaining any numbers, symbols or reference points. This is later used to complete a finished sketch with more details. The sketch is prepared by measuring the scene boundaries and significant items from fixed points using various techniques to obtain accurate distances and positioning. Important identifying information is included in a title block.