Crime Scene Investigators, also known as CSIs, have played an essential role in protecting citizens by proving who is guilty and who is innocent. CSIs use a great deal of scientific and mathematical expertise to solve crimes while earning a decent income. They specialize in forensic science to examine crime scenes and recover important evidence (Career Cruising). CSIs must photograph/draw crime scenes, take measurements, make observations, testify against criminals in court, and collect, package, label, document, and analyze evidence (Career Cruising). All of these tasks that CSIs must complete require them to handle a variety of tools including: cameras, tripods, flashlights, notebooks, utensils for collecting physical evidence, tape measures, rulers, microscopes, fingerprinting kits and in some cases even guns (Cruise Career). CSI agents collect different types of evidence when investigating a crime (Byrd). The first type of evidence is testimonial evidence, i.e. the answers provided by CSIs who question suspects and witnesses (Byrd). Physical evidence, which is the other type of evidence, is any type of three-dimensional evidence collected at a crime scene (Byrd). Although different CSI teams from different areas of the world may consist of multiple branches, including: detectives, technicians, medical examiners, scientists and laboratory analysts, they still use forensics, which is science and technology, to investigate crimes ( Zullo). There is always crime, but when there are no current cases; CSIs date back to old/previous cases (McFadden). Although all teams of crime scene investigators investigate the same case, their jobs and salaries typically vary (Florida Tech University Online). There are four different branches on some...... half of the paper ......g with a decent income. Works Cited Byrd, Mike. Description of the duties of the crime scene investigator. Network. November 26, 2013. www.crime-scene-investigator.net.Crime Scene Investigator. Career cruise. Np, nd Web. November 22, 2013. www.careercruising.com.Crime Scene Investigator. Network. November 26, 2013. www.careerprofiles.info.Florida Tech University Online. CSI professional and salary profile. Network. November 25, 2013. www.floridatechonline.com.Hallcox, Jarret. Behind the Yellow Tape: Traveling with some of America's hardest-working crime scene investigators. New York: Berkley Books, 2009. McFadden, Jane. Telephone interview. November 26, 2013.Miller, Connie. Crime scene investigators: discover the truth. Mankato: Capstone Press, 2008.Shone, Rob. Crime scene investigators. New York: Rosen Pub, 2008. Zullo, Allan. Crime scene investigators. New York: Scholastica, Inc., 2008.