Murders and other crimes happen in the most difficult places to find. This is because the criminals who are involved most probably don't want people to find out what they did and where they did it. They don't like leaving clues behind for police forces to pick up on to track them down. This is what makes it difficult to track down killers. If you don't find the clues, you won't know what to look for.

The most important thing to remember is that crime scenes can get contaminated. The longer a crime scene sits around, the more contaminated it can get and the less evidence police can get. That is why they have to gather as much information as they can from the crime scene. They also have to make sure that unauthorized personnel cannot tamper with the crime scene. They use different ways to mark off the scene so that they can secure it for data gathering. They even use bright blank flags and police lines just to pinpoint areas that do permit access without proper clearance.

Sometimes, the crime scene is composed of different sectors that hold different kinds of information. There are also times that the crime scene is composed of multiple smaller crime scenes. These have to be marked separately in order for the police forces to effectively gather data. They also have to make sure that the evidence they gather does not get mixed up. They use blank flags with different colors to indicate different areas that they need to scour.