This detective training film, made by West Yorkshire Police, shows investigators at a reconstructed crime scene trying to piece together the series of events that led to the murder of a man. The investigators show the correct way a crime scene should be handled, stringently following the taught procedures. However, the educational value of this film is diminished by missing a sound track, as many scenes contain large portions of dialogue. Title - Preserve or contaminate it's down to...

This detective training film, made by West Yorkshire Police, shows investigators at a reconstructed crime scene trying to piece together the series of events that led to the murder of a man. The investigators show the correct way a crime scene should be handled, stringently following the taught procedures. However, the educational value of this film is diminished by missing a sound track, as many scenes contain large portions of dialogue. Title - Preserve or contaminate it's down to you. The film opens with still photos of a graphic nature, which some viewers might find disturbing. The still photos show gruesome images of actual murder victims, crime scenes and weapons. There is then a drawing that depicts a woman standing up, with the following still showing a reconstruction her face. A map of Heckmondwike, Dewsbury, has several arrows pointing to different locations with headings that read, 'Sighting', 'Mr Cullen's house' and, 'Holingbank Lane'. A map then shows the area of Dewsbury, Huddersfield and Halifax, with a route highlighted in black marker pen. A man lies dead in a field next to a large mound of rubble. An officer stands guarding the entrance to the field and the camera pans across to show the adjacent road. Two investigators then chat to the officer as he takes notes. A measuring tape is then shown running along a gradient in the field, before more shots show the investigators continuing to discuss the case. The investigators are shown to the man's body, after which a photographer arrives on scene. After a prolonged chat with the investigators, the photographer sets up his tripod and camera and begins to take photos of the undisturbed crime scene. The photographer uses an instant developing film, and he holds developed photo of the deceased man up to the camera. There are then close ups of the victim, which show that his hands have been bound with rope, before there are views of the wider area; capturing the debris in more detail. Two doctors arrive on the scene and converse with the investigators and guarding officer. The two doctors are then lead by the investigators up the slope to the crime scene, where they examine the body; taking detailed notes on all injuries. A doctor then swabs the deceased males head with a cotton bud. The other doctor puts on rubber gloves and rolls the body to have a look beneath. Plastic bags are then placed over the body's extremities, before being wrapped in plastic and carried away. An investigator then begins to sift through the rubble and finds a spent firearm cartridge. A senior officer then chats with the investigator, followed by a man in brown suit. Samples from the crime scene are then collected, and a close up shows a jar with a label that reads, 'soil sample - found near head'. An investigator then uses tweezers to carefully check through the grass. Upon finding a small fragment with the tweezers, the investigator places the evidence in a jar and the photographer takes another picture. An investor uses a magnifying glass to inspect the surface of the stone fence. In the next sequence, the investigators try to re-enact the murder. A group of people then stand round one of the investigators, who pretends to play the role of the victim, and he is rolled into different positions. As part of the re-enactment, a female investigator holds a shotgun to investigators head. The final shots show the crime scene in its original state. Title - Touch nothing. Title - Take nothing away. The next few shots some of the equipment used, which includes a measuring tape, metal poles, a stills camera and a clip board. Title - Produced by the West Yorkshire Metropolitan Police. Title - Photography - Rex Matthews. Sound - Gerald Hancock. Title - The end.