Inside the FBI Podcast: The Federal DNA Database Unit

SPEAKER_1 (0:01)

The FBI Laboratory provides critical support to the Bureau's mission. This is especially true of the units who support the Combined DNA Index System, or CODIS, an FBI-run national database that contains DNA profiles submitted by participating federal, state, and local forensic laboratories. Crime labs can use CODIS to search for links between DNA captured at crime scenes and the individuals profiled in the database. In this way, CODIS directly supports our efforts to crush violent crime by speeding investigations and enabling investigative breakthroughs. On this episode of our podcast, we'll meet the Bureau's Federal DNA Database Unit, a super group of laboratory and biometric support experts tasked with ensuring that federally collected DNA samples make it into CODIS. We'll explain how the unit creates the genetic profiles that power CODIS, discuss how they recently overcame a historic processing backlog, and find out what's next for the team. This is Inside the FBI.

The Federal DNA Database Unit, or FDDU, executes a unique but critical mission.

Federal law enforcement agencies, including DOJ components like the FBI, are required by law to capture DNA samples and biographic information under certain circumstances, when they make federal arrests, when they detain non-US citizens, and after a person has been convicted of a crime. These agencies then send each sample, along with information about its source, to the FBI laboratory. Once the samples reach the lab, FDDU experts get to work. First, they cut out a small portion of each sample.

Michael S. (1:54)

They are working with scientific instrumentation. We call it punch instruments.

SPEAKER_1 (1:58)

That's Michael S., a veteran FBI biometrics examiner, who leads the Federal DNA Database Unit.

Michael S. (2:04)

This is when we take the sample, which is now located on a little card, and they essentially have a scientific version of a hole punch. They basically line it up and punch a 1.2 millimeter hole in that sample card, which contains the DNA. And that is one of the hardest, most manual processes in terms of time commitment.

SPEAKER_1 (2:25)

That hole punch then drops into a DNA plate that is run through lab machinery that extracts and amplifies, or generates copies of, the DNA.

Next, the team uses other equipment to map limited parts of the sample source's DNA to generate a genetic profile. Federal law limits how much of a person's genome the FBI is allowed to map for a DNA profile. As a result, our experts examine the minimum number of points needed to definitively distinguish one person's DNA from another's.

Michael S. (2:53)

Typically, we look at 20 different locations in your DNA. Each of those locations are attributed to two numbers. One comes from your mom, and one comes from your dad, and so that string of then 40 numbers is what is produced by our instrumentation. We call it genetic analyzers. It produces what's called an electrophorogram, which is a fancy way of saying a graph that shows you what your genetic profile is.

SPEAKER_1 (3:18)

Then, FDDU checks that profile for quality.

Michael S. (3:22)

Our examiners are going through and looking at the data to make sure it meets certain thresholds, to make sure there's no quality problems with the data, to make sure it's consistent. You can see a number of problems when you are trying to develop a genetic profile that will cause it not to be able to go into CODIS. The nice thing is, if you do see those things, we have recovery steps and recovery processes in order to be able to process the sample again and be able to hopefully get a full profile that we can then add to CODIS.

There are scenarios where we ultimately don't get a genetic profile and then we do send out a notice to the collection agency saying, if possible, can you recollect? So it does happen, but it's a fairly small percentage of what we see.

SPEAKER_1 (4:04)

Once FDDU's biometrics examiners determine that a DNA profile is up to snuff, they add it to CODIS. They also store the corresponding biographic information in FDDU databases to ensure the sample can always be traced back to its human source. Once a sample has been added to CODIS, it is then searched daily against DNA from crime scenes or evidence kits to potentially link individuals to crimes.

In many ways, CODIS is a super database. The national level database is actually composed of a number of smaller criminal justice DNA databases. It also contains DNA profiles contributed by state and local forensic laboratories. Even though it's a team effort, the FBI lab has historically done a lot of lifting to the tune of about 100,000 samples a year. But a federal regulation change in 2020 that required the US Department of Homeland Security to start collecting DNA samples from federal arrestees and non-US citizen detainees, as well as workplace challenges related to the COVID-19 pandemic caused a surge in the unit's workload.