Where Does Forensic Evidence at a Crime Scene Get Sent for Testing?

crime lab

Are you sending crime scene evidence to a crime lab in your fiction book? This post tells you about the different types of crime labs and how they work.

You've written the crime scene portion of your murder mystery. You've had the crime scene people collect the evidence and package it up, and off it goes to the crime lab... or does it?

Did you know that not all crime labs are the same?

Crime labs differ in the services they offer and the jurisdictions they serve, and certain forensic examinations are performed in specialized facilities outside of the crime lab. The law enforcement agency can also pay to send it to a private lab if their local laboratory doesn’t provide a specific service or if they want their results back faster.

If you want the forensic results in your crime fiction book to be realistic, you need to make sure you have your characters send the evidence to the right place.

This post discusses the three different types of crime labs, what types of analyses are performed, and helpful hints on how to describe crime labs in your fiction book.

3 Different Types of Crime Labs

There are three main types of crime labs: typical crime labs, specialize forensic disciplines and research labs, and private labs.

Typical Crime Labs

A typical crime lab is what you generally see on TV (except for Bones) and is usually associated with a law enforcement agency, medical examiner, or coroner at the city, county, state, regional, or federal level.

Whether a jurisdiction has a crime lab largely depends on funding and population. Crime labs are very expensive to set up and maintain (we’re talking millions of dollars).

A small town with low crime will not have forensic lab facilities. The low crime rate does not justify the expense. A large city with a lot of crime probably would.

City Crime Labs

City labs serve the police department they’re affiliated with. Typically, only one law enforcement agency submits cases (along with district/county attorneys). City labs are usually found in larger cities and there is usually only one public crime lab per city.

A city lab might be a full-service lab, or it may only offer a handful of services.

Cities that have their own crime lab include San Francisco, California; Kansas City, Missouri; and Austin, Texas. You can do some internet research to see if the city in your book has its own crime lab.

County Crime Labs

A county crime lab receives cases from all cities/towns in that county that don’t have their own lab, as well as the county law enforcement agency (i.e., cases that are outside city limits but still in that county). County labs are typically affiliated with sheriff’s offices.

Regional Crime Labs

A regional crime lab covers a specific region of a state consisting of multiple counties and serves the agencies within that area. An example of a regional crime lab is the Northern Colorado Regional Crime Laboratory.

State Crime Labs

A state crime lab system provides services to agencies within a state that do not have their own laboratory services. States with small populations might have just one lab for the entire state, similar to my previous employer, or they might have an entire system of labs. Not all labs within the system are full-service labs.

An example of a multi-lab state system is the Washington State Patrol, which has seven regional labs: Seattle (10), Spokane (10), Tacoma (10), Marysville (7), Vancouver (6), Kennewick (3), and Olympia (2). Each lab does not provide the same services. The numbers in parentheses indicate the number of services provided in each lab.

An example of a single-lab system is the Wyoming Division of Criminal Investigation, which has one lab that serves the entire state (in Cheyenne).

Federal Crime Labs

Federal labs serve both federal and local agencies. The FBI forensic laboratory performs a variety of laboratory services.

Forensic services that are commonly found in traditional crime labs include:

  • Biology/DNA (including CODIS)
  • Explosives
  • Fire debris
  • Trace evidence
  • Firearms/toolmarks
  • Latent prints
  • Toxicology (including blood alcohol)
  • Controlled substances
  • Document examinations
  • Digital forensics

Most typical crime labs affiliated with a law enforcement agency provide their services at no cost to the agency. If the defense wants testing, they have to send the evidence to a private laboratory and pay fees. Specialized services also incur fees.

Specialized Forensic Disciplines and Experts

You’ve probably heard about all these new and exciting scientific methods in the field of forensic science, such as genetic genealogy, forensic phenotyping, and new forensic hair techniques, and other forensic disciplines, such as forensic entomology, soil analysis, and bite marks.

These techniques can provide helpful information in criminal investigations; however, they’re not performed at traditional crime labs.

Specialized forensic techniques are performed by individuals affiliated with research labs, typically at academic institutions.

When you hear about a study that describes a brand new forensic method, that work was probably performed in a private company. 

A law enforcement agency might send out evidence to these types of labs when typical forensic analyses are either not possible or did not yield useful results. 

Services that are typically performed in specialized laboratories/companies or by non-crime lab experts include:

  • Forensic entomology
  • Facial reconstruction
  • Paternity
  • Forensic pathology
  • Forensic dentistry
  • Animal/wildlife forensics
  • Mitochondrial DNA
  • Forensic microbiology
  • Forensic genealogy
  • Forensic phenotyping
Private Crime Labs

Private crime labs can perform the same types of testing that a typical crime lab can, but it charges a fee for its services. 

Law enforcement might choose to send evidence to a private lab to speed up the results or because they need a service that their local crime lab can't perform (such as forensic paternity or mitochondrial DNA).

Where to Send the Forensic Evidence from Crime Scenes in Your Fiction Book

Where the evidence gets sent depends on multiple factors. I've created a step-by-step guide below to help you figure out where to send the forensic evidence in your book.

  1. List out all of the forensic evidence in your book.
  2. Look at the lists I provided above and write down where you're going to have the police send each piece of evidence.
  3. If you have specialized evidence that falls outside what a typical crime lab can analyze, you can make up a new character or company that will analyze the evidence.
  4. For forensic testing at a typical crime lab, you can do some internet research to determine where the law enforcement agency in your book sends their evidence. If you're using a fictional agency, I suggest modeling it on a real agency and then making some tweaks as you see fit.
  5. Agencies use a "nesting doll" strategy when figuring out where to send their evidence. If the agency has a crime lab, the evidence goes there. If they don't, then it goes to the county crime lab. If there's no county crime lab, then it goes to the state lab.
  6. A technique for getting forensic results back faster is to send it to a private lab. Just keep in mind that the police department will need to pay for it. Options for payment are seizure funds, grant money, or taking it from a different line item in the budget.
  7. A final editing note: If you’re referring to a real crime lab in your book, make sure you look up the name, especially if it’s a state agency. It’s one of the items I always make sure to check when I edit crime fiction books. State law enforcement agencies have a wide variety of names. Some examples include the Texas Department of Public Safety, the Florida Department of Law Enforcement, the Illinois State Police, the Nebraska State Patrol, and the Ohio Bureau of Criminal Identification and Investigation.


You should now be familiar with the different types of crime labs and how they work and know where to send the forensic evidence in your crime fiction book. Sending it to the right place will help make the forensics in your book more accurate and believable.


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