Imagine this. You step into a store that was robbed. The thief broke a window, and glass covers the floor. You look out the window and see muddy shoeprints. You follow them and see a vehicle's tire marks. As a crime scene investigator, this is your workplace. You find clues to help catch the thief.
A crime scene investigator works with police. The investigator searches for fingerprints. She also looks for hair and blood--important evidence that contains a person's DNA. A person's fingerprints and DNA are both unique. This evidence is valuable to police.
A crime scene investigator photographs and measures. For example, the investigator may measure shoeprints and the space between them. Shoeprints give clues about many things, including the size and gender of the wearer. The investigator photographs tire marks left on the road. These marks give clues about the thief's vehicle and the direction it traveled.
How do police catch a thief? They do it with the help of a crime scene investigator. Crime scene investigators' evidence makes it more possible for police to catch a criminal.