At crime scenes, forensic science technicians typically do the following:

• Analyze crime scenes to determine what and how evidence should be collected
• Take photographs of the crime scene and evidence
• Make sketches of the crime scene
• Record observations and findings, such as the location and position of evidence
• Collect evidence, including weapons, fingerprints, and bodily fluids
• Catalog and preserve evidence for transfer to crime labs

In laboratories, forensic science technicians typically do the following:

• Perform chemical, biological, and microscopic analyses on evidence taken from crime scenes
• Explore possible links between suspects and criminal activity, using the results of DNA or other scientific analyses
• Examine digital media for pertinent information
• Consult with experts in specialized fields, such as toxicology (the study of poisons and their effect on the body) and odontology (a branch of forensic medicine that concentrates on teeth)
• Reconstruct crime scenes

Forensic science technicians may be generalists who perform many or all of the duties listed above or they may specialize in certain techniques and sciences. Generalist forensic science technicians, sometimes called criminalists or crime scene investigators, collect evidence at the scene of a crime and perform scientific and technical analysis in laboratories or offices.

Forensic science technicians who work primarily in laboratories may specialize in the natural sciences or engineering. These workers, such as forensic pathologists and latent print examiners, typically use chemicals and laboratory equipment such as microscopes when analyzing evidence. They also may use computers to examine fingerprints, DNA, and other evidence collected at crime scenes. They often work to match evidence to people or other known elements, such as vehicles or weapons. Most forensic science technicians who perform laboratory analysis specialize in a specific type of evidence, such as DNA or ballistics.

Some forensic science technicians, called forensic computer examiners or digital forensics analysts, specialize in computer-based crimes. They collect and analyze data to uncover and prosecute electronic fraud, scams, and identity theft. The abundance of digital data helps them solve crimes in the physical world as well. Computer forensics technicians must adhere to the same strict standards of evidence gathering found in general forensic science because legal cases depend on the integrity of evidence.

All forensic science technicians prepare written reports that detail their findings and investigative methods. They must be able to explain their reports to lawyers, detectives, and other law enforcement officials. In addition, forensic science technicians may be called to testify in court about their findings and methods.