5 Methods Forensic Scientists Use to Solve Crime

Forensic scientists have a unique crime scene investigation route, as they usually try to understand a crime from its least apparent vantage points. Read about five methods forensic scientists use to solve crime to learn more about this intriguing facet of crime scene investigation.


One effective method that forensic scientists use to solve crimes is the analysis of ballistics. In crime scene investigations, ballistics almost always means bullets. Ballistic forensics falls into four main categories: internal, external, terminal, and transitional ballistics.

Each of these categories serves a different function. But essentially, forensic scientists can examine these different types of ballistics to identify ammunition, match it to a specific firearm, and use that to help law enforcement narrow down their list of suspects.

Polymerase Chain Reaction

Polymerase chain reaction, or PCR, is a fascinating technique investigators use to “fill in the blanks” of DNA evidence that’s compromised or deteriorated in some way. The process takes a single copy of DNA. Then, it is replicated thousands or even millions of times until the DNA sequence is sufficient, is thoroughly evaluated, and matched to a potential suspect. As a result, PCR has become essential to solving crimes whose scenes contain DNA but lack enough evidence to yield conclusive results.  


Chromatography is a delicate process used to separate and identify components of a mixture. There are various chromatography methods, but the most effective for forensic scientists are gas and high-performance liquid chromatography. Gas chromatography helps identify and analyze bodily fluids—like blood—and find poison in a body.

High-performance liquid chromatography evaluates residues, gunpowder, fibers, or toxins. Forensic scientists use chromatography to understand a crime scene on a microscopic level, helping them deduce the specific circumstances of the crime.

Luminol Spray

Perhaps one of the most popular methods of forensic investigation is the use of luminol spray. This simple spray has a chemical reaction to the hemoglobin and iron found in the blood. So, when luminol hits traces of blood, it creates a blue glow against the backdrop of a darkened room, even if a suspect washes or scrubs the blood. Luminol is especially effective for investigating crime scenes manipulated by a suspect to cover traces of blood or DNA.

Fingerprint Analysis

Another famous method of forensic investigation is fingerprint analysis. While there are hundreds of theoretical techniques for this type of examination, only 20 are accurate enough to use in forensic labs worldwide. The most common technique among crime scene investigations is dusting a crime scene with black powder for prints.

If prints exist, investigators raise the prints using a delicate adhesive that won’t contaminate the print. Later, the findings are sent off to the lab to evaluate for matches. This method can determine how many suspects are involved and, in some cases, the identity of a suspect.

Forensic scientists are integral in helping law enforcement determine the critical characteristics of a crime scene. They utilize various approaches, but these five methods forensic scientists use to solve crime are the most effective.

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Written by Logan Voss

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