What Methods Do Forensic Scientists Use in Investigations?

Forensic scientists are an essential part of the crime investigation team.

A necessary part of any action to solve a crime, forensic investigation is far more complex than it is often portrayed by Hollywood and the mass media. A thorough investigation may involve such diverse law enforcement professionals as animators, digital investigators and garden-variety police officers. However, forensic scientists do much of the investigatory work that relates directly to evidence.

Bodily Fluids

Often, crime scenes are dripping with bodily fluids. Depending on the nature of the crime, these may include blood, sweat, semen, urine and feces. Forensic scientists collect these from the scene of the crime using cotton swabs and airtight vials to avoid contamination. They then bring the fluids back to the laboratory for DNA testing. They also check the fluids for trace amounts of other material, such as skin flakes and fluids from other sources.

Weapons and Other Objects

Once collected from the crime scene, weapons and other objects are transported to the laboratory carefully and in sterile containers to avoid contamination. Forensic scientists then check the objects carefully for fingerprints, stray hairs, bodily fluids and other evidence. This evidence is then analyzed and checked against the Federal Bureau of Investigation's fingerprint database.

Clothing and Shoes

Clothing and shoes are rich sources of evidence for forensic scientists. Clothing that is found on victims or survivors of violent crime may bear stray hairs, skin flakes, fibers from the perpetrator's clothing and other pieces of trace evidence. Suspects may also have pieces of the crime scene clinging to their clothing. To collect this evidence, forensic scientists collect traces with tweezers and package them in sterile bags; lift fibers with sterile tape, which is then packaged for further testing; or vacuum the evidence off the suspect or victim's clothing.

Reconstruction

Reconstruction of the crime is a large part of what forensic scientists do on the actual scene of the crime. From the placement of the body relative to where the bullet is found, a forensic scientist may be able to tell where the gun was fired. Blood spatters also tell a story to the educated eye; from the pattern of blood on a wall or floor, a forensic scientist may be able to not only pinpoint where the assault happened, but what the weapon was and even the approximate height of the perpetrator.

References

• All About Forensic Science: Crime Scene Collection Techniques
• Explore Forensics: Bodily Fluids in Forensic Science