CSI or crime scene investigation, is the use of modern science technologies to analyse information found at the crime scene to better help the police force to solve the case. The information gathered from the crime scene investigation can be use as evidence in court to bring the criminal to justice.
about the TV show CSI, it a different story, there are certain parts of the show which is accurate and there are certain parts of the show which is inaccurate.
below are the accurate ones
1. ballistic fingerprinting - use the find the gun used in the crime scene
2. forensic chemistry - use of chemistry to find out about the chemical changes which could occur during the crime, allows the police to reconstruct the time line of the crime scene.
3. forensic identification - use of forensic science to find out about the identity of a certain person or a certain product, for person, it the use of fingerprint identification, DNA test and so on, for product identification, checking the labels and information store in technological products like computers to reveal what information has been stored, deleted and recovered.
4. forensic facial reconstruction - use of computer technology to create the almost 100% accurate facial look of a person. this means that the police have the ability to know what a person looks like even if he is only a pile of bones.
now that's about all the different technology used in the real crime scene investigation, all the others shown in the TV series CSI is fake, the ones listed above is real.