Tag Archives: dna

The National Institute of Standards and Technology has published a draft report entitled DNA Mixture Interpretation: A Scientific Foundation Review.

As NIST explains:

This report, currently published in draft form, reviews the methods that forensic laboratories use to interpret evidence containing a mixture of DNA from two or more people.

From https://www.nist.gov/dna-mixture-interpretation-nist-scientific-foundation-review

The problem of mixtures is more pronounced in DNA analysis than in analysis of other biometrics. You aren’t going to encounter two overlapping irises or two overlapping faces in the real world. (Well, not normally.)

You can certainly encounter overlapping voices (in a recorded conversation) or overlapping fingerprints (when two or more people touched the same item).

But there are methods to separate one biometric sample from another.

It’s a little more complicated when you’re dealing with DNA.

Distinguishing one person’s DNA from another in these mixtures, estimating how many individuals contributed DNA, determining whether the DNA is even relevant or is from contamination, or whether there is a trace amount of suspect or victim DNA make DNA mixture interpretation inherently more challenging than examining single-source samples. These issues, if not properly considered and communicated, can lead to misunderstandings regarding the strength and relevance of the DNA evidence in a case.

From the Abstract in https://doi.org/10.6028/NIST.IR.8351-draft%C2%A0

As some of you know, I have experience with “rapid DNA” instruments that provide a mostly-automated way to analyze DNA samples. Because these instruments are mostly automated and designed for use by non-scientific personnel, they are not able to analyze all of the types of DNA that would be analyzed by a forensic laboratory.

Therefore, this draft document is silent on the topic of rapid DNA, despite the fact that co-author Peter Vallone has years of experience in rapid DNA.

I am not a scientist, but in my view the absence of any reference to rapid DNA strongly suggests that it’s premature at this time to apply these instruments to DNA mixtures, such as rape cases in which both the assailant’s and the victim’s DNA are present in a sample.

Granted, there may be rape cases in which the DNA of the assailant may be present with no mixture.

You have to be REALLY careful before claiming that rapid DNA instruments can be used to wipe out the backlog of rape test kits. However, rapid DNA can be used to clear less complicated DNA cases so that the laboratories can concentrate on the more complex cases.

People have been talking about the “CSI effect” for decades.

In short, the “CSI effect” is characterized as the common impression that forensic technologies can solve crimes (and must be used to solve crimes) in less than an hour, or within the time of a one-hour television show.

When taken to its extreme, juries may ask why the law enforcement agency didn’t use advanced technological tools to solve that jaywalking case.

Advanced technological tools like DNA, which has been commonly perceived to be the tool that can solve every single crime.

Well, that and video, because video is powerful enough to secure a conviction. But that’s another story.

Can DNA result in an arrest in a Denver homicide case?

A case in point is this story from KDVR entitled “DNA in murder case sits in Denver crime lab for 11 months.”

This is a simple statement of fact, and is not that surprising a statement of fact. Many crime labs are inundated with backlogs of DNA evidence and other forensic evidence that has yet to be tested. And these backlogs ARE creating difficulties in solving crimes such as rapes.

But when you read the article itself, the simple statement of fact is painted as an abrogation of responsibility on the part of law enforcement.

A father is making an emotional plea and putting up $25,000 of his own money to help find his son’s killer.

He is also asking the Problem Solvers to look into the time it has taken for DNA evidence to be tested in this case and others.

Tom O’Keefe said it’s taking too long to get answers and justice.

From this and other statements in the article, a picture emerges of an unsolved crime that can only be solved by the magical tool of DNA. If DNA is applied to this, just like they do on TV, arrests will be made and the killer will be convicted.

So why is it taking so long to do this?

Why is justice not being served?

KDVR is apparently not run by impassioned activists, but by journalists. And it is important from a journalistic perspective to get all sides of the story. Therefore, KDVR contacted the Denver Police Department for its side of the story.

The Denver Police Department has identified all parties involved, and the investigation shows multiple handguns were fired during this incident. While this complex case remains open, which limits details we can provide, we can verify that a significant amount of forensic work has been completed, but some remains. Investigators believe the pending forensic analysis can potentially support a weapon-related charge but will not further the ongoing homicide investigation.

OK, let’s grant that they’re not trying to identify an unknown assailant, since “all parties involved” are known.

But once that DNA is tested, isn’t that going to be the magic tool that provides the police with probable cause to arrest the killer?

Um, no.

Even IF the DNA evidence DOES happen to show a significant probability that an identifiable person committed the homicide, that in itself is not sufficient reason to arrest someone.

Why not?

Because you can’t arrest someone on DNA evidence alone.

DNA evidence can provide an investigative lead, but it has to be corroborated with other evidence in order to secure an arrest and a conviction. (Don’t forget that the evidence has to result in a conviction, and in most of the United States that requires that the evidence show beyond a reasonable doubt that the person committed the crime.)

Why was a serial killer in three European countries never brought to justice, despite overwhelming DNA evidence?

Reasonable schmeasonable.

If DNA ties someone to a crime, then the person committed the crime, right?

Let’s look at the story of a serial killer who terrorized Europe for over a decade, even though ample DNA evidence was found at each of the murder scenes, beginning with this one:

In 1993, a 62-year-old woman was found dead in her house in the town of Idar-Oberstein, strangled by wire taken from a bouquet of flowers discovered near her body.

Nobody had any information on what might have happened to Lieselotte Schlenger. No witnesses, no suspects, no signs of suspicious activity (except for the fact that she’d been strangled to death with a piece of wire, of course). But on a bright teacup near Schlenger, the police found DNA, the only clue to surface at all.

The case went cold, given that the only lead was the DNA of an unknown woman, and there was no match. Yet.

Eight years later, in 2001, there was a match when the same woman’s DNA was found at a murder scene of a strangulation victim in Freiburg, Germany. Police now knew that they were dealing with a serial killer.

But this time, the woman didn’t wait another eight years to strike again.

Five months after the second murder scene, her DNA showed up on a discarded heroin syringe, after a 7-year-old had stepped on it in a playground in Gerolstein. A few weeks later it showed up on an abandoned cookie in a burgled caravan near Bad Kreuznach, like she’d deliberately spat out a Jammy Dodger as a calling card. It was found in a break-in in an office in Dietzenbach, in an abandoned stolen car in Heilbronn, and on two beer bottles and a glass of wine in a burgled bar in Karlsruhe, like she’d robbed the place but stuck around for a few cheeky pints.

And her activities were not confined to Germany.

Over the apparent crime spree, her DNA was sprayed across an impressive 40 crime scenes in Austria, southern Germany, and France, including robberies, armed robberies, and murders.

In 2009, the case took an even more bizarre turn.

Police in France had discovered the burned body of a man, believed to be from an asylum seeker who went missing in 2002. During his application, the man had submitted fingerprints, which the police used to try and confirm his identity. Only, once again, they found the DNA of the phantom.

“Obviously that was impossible, as the asylum seeker was a man and the Phantom’s DNA belonged to a woman,” a spokesperson for the Saarbrücken public prosecutor’s office told Spiegel Online in 2009.

But how could this be?

DNA evidence had tied the woman, or man, or whatever, to six murders and numerous other crimes. There was plenty of evidence to identify the criminal.

What went wrong?

Well, in 2009 police finally figured out how DNA evidence had ended up at all of these crime scenes in three countries.

The man’s death led to an explanation of the case: there was no serial killer, and the DNA could be traced to a woman working in a packing center specializing in medical supplies. It was all down to DNA contamination.

Well, couldn’t that packing woman be convicted of the serial murders and other crimes, based upon the DNA evidence?

No, because there was no other evidence linking the woman to the crimes, and certainly “reasonable doubt” (or the European criminal justice equivalent) that the woman was also the dead male asylum seeker.

This is why DNA is only an investigative lead, and not evidence in and of itself.

But the Innocence Project always believes that DNA is authoritative evidence, right?

Even those who champion the use of DNA admit this.

If you look through the files of people exonerated by the Innocence Project, you find a common thread in many of them.

Much of the evidence gathered before the suspect’s original conviction indicated that the suspect was NOT the person who committed the crime. Maybe the family members testified that the suspect was at home the entire time and couldn’t have committed the crime in question. Or maybe the suspect was in another city.

However, some piece of evidence was so powerful that the person was convicted anyway. Perhaps it was eyewitness testimony, or perhaps something else, but in the end the suspect was convicted.

Eventually the Innocence Project got involved, and subsequent DNA testing indicated that the suspect was NOT the person who committed the crime.

This in and of itself didn’t PROVE that the person was innocent, but the DNA test aligned with much of the other evidence that had previously been collected. It was enough to cast a reasonable doubt on the conviction, allowing the improperly convicted suspect to go free.

But there are some cases in which the Innocence Project says that even DNA evidence is not to be trusted.

Negligence in the Baltimore Police Department’s crime lab tainted DNA analysis in an unknown number of criminal cases for seven years and raises serious questions about other forensic work in the lab, the Innocence Project said today in a formal allegation that the state is legally required to investigate.

DNA contamination, the same thing that caused the issues in Europe, also caused issues in Baltimore.

And there may be other explanations for how a person’s DNA ended up at a crime scene. Perhaps a police officer was careless and left his or her DNA at a crime scene. Perhaps someone was at a crime scene and left DNA evidence, even though that person had nothing to do with the crime.

In short, a high probability DNA match, in and of itself, proves nothing.

Investigative leads and reasonable doubt are very important considerations, even if they don’t fit into a one-hour TV show script.

A July Bredemarket post on Facebook has garnered some attention in September.

I wanted to answer some questions about rapid DNA use in a booking station, how (and when) DNA is used in booking (arrests), what an “investigative lead” is, and whether acquiring DNA at booking is Constitutional.

(TL;DR on the last question is “yes,” per Maryland v. King.)

Are rapid DNA booking stations a Big Brother plot?

The post in question was a Facebook post to the Bredemarket Identity Firm Services Facebook group. I posted this way back in July, when Thermo Fisher Scientific became the second rapid DNA vendor (of two rapid DNA vendors; ANDE is the other) whose system was approved by the U.S. Federal Bureau of Investigation (FBI) for use as a law enforcement booking station.

When I shared this on Facebook, I received some concerned comments:

“Big brother total control”

“Is this Constitutional??? Will the results of this test hold up in courtrooms???”

I’ll address the second question later: not just in regard to rapid DNA, but to DNA in general. At this point, however, I will go ahead and say that the use of rapid DNA in booking was authorized legislatively by the Rapid DNA Act of 2017. This was followed by over three years of procedural stuff until rapid DNA booking station use was authorized this year.

To accurately state what “rapid DNA booking station use” actually means, let me refer to the FBI’s language, starting with the purpose:

The FBI Laboratory Division has been working with the FBI Criminal Justice Information Services (CJIS) Division and the CJIS Advisory Policy Board (CJIS APB) Rapid DNA Task Force to plan the effective integration of Rapid DNA into the booking station process.

By way of definition, a “booking station” is a computer that processes individuals who are “booked,” or arrested. The FBI’s plan was that (when authorized by federal, state, or local law) when an arrested individual’s fingerprints were captured, the individual’s DNA would be captured at the same time. (Again, only when authorized.)

The use of the term “reference sample buccal (cheek) swab” is intentional. The FBI’s current development and validation efforts have been focused on the DNA samples obtained from known individuals (e.g., persons under arrest). Because known reference samples are taken directly from the individual, they contain sufficient amounts of DNA, and there are no mixed DNA profiles that would require a scientist to interpret them. For purposes of uploading or searching CODIS, Rapid DNA systems are not authorized for use on crime scene samples.

“CODIS,” by the way, is the Combined DNA Index System, a combination of federal, state, and local systems.

“Rapid DNA” is an accelerated, automated DNA method that can process DNA samples in less than two hours, as opposed to the more traditional DNA processes that can take a lot longer.

The FBI is NOT ready to use rapid DNA to solve crimes, although some local police agencies have chosen to do so. And until February of this year, the FBI was not ready to use rapid DNA in the booking process either.

So what has been authorized?

The Bureau recognizes that National DNA Index System (NDIS) approval of the Rapid DNA Booking Systems and training of law enforcement personnel using the approved systems are integral to ensuring that Rapid DNA is used in a manner that maintains the quality and integrity of CODIS and NDIS.

Rapid DNA Booking System(s) approved for use at NDIS by a law enforcement booking station are listed below.

ANDE 6C Series G (effective February 1, 2021)

RapidHIT™ ID DNA Booking System v1.0 (effective July 1, 2021) 

If you read the FBI rapid DNA page, you can find links to a number of forensic, security, and other standards that have to be followed when using rapid DNA in a booking environment.

But those aren’t the only restrictions on rapid DNA use.

Can ANY law enforcement agency use rapid DNA in booking?

Um, no.

According to the National Conference of State Legislatures (2013; see PDF), not all states authorize the taking of DNA after an arrest. As of 2013, 20 states did NOT allow the taking of DNA from individuals who had been arrested but not convicted. And of the 30 remaining states, some (such as Connecticut) only allowed taking of DNA for “serious felonies,” some (such as California) for all felonies, and various mixtures in between. Oklahoma, for example, only allowed taking of DNA for “aliens unlawfully present under federal immigration law.”

Now, of course, a rogue police officer could take your DNA when not legally authorized to do so. Then again, a rogue restaurant employee could put laxatives in your food; that doesn’t mean we outlaw laxatives.

An “investigative lead”

So let’s say that you’re arrested for a crime, and your state allows the taking of DNA for your crime at arrest, and your local law enforcement agency has a rapid DNA instrument.

Now let’s assume that your DNA is searched against a DNA database of unsolved crimes, and your DNA matches a sample from another crime. What happens next?

If there is a match, police will likely want to take a closer look.

Wait a minute. There’s a DNA match! Doesn’t that mean that the police can swoop in and arrest the individual, and the individual is immediately convicted?

Um, no. Stop trusting your TV.

It takes more than DNA to convict a person of a crime.

While DNA can provide an investigative lead, DNA in and of itself is not sufficient to convict an individual. The DNA evidence usually has to be supported by additional evidence.

Especially since there may be other explanations of how the DNA got there.

In 2011, Adam Scott’s DNA matched with a sperm sample taken from a rape victim in Manchester—a city Scott, who lived more than 200 miles away, had never visited. Non-DNA evidence subsequently cleared Scott. The mixup was due to a careless mistake in the lab, in which a plate used to analyze Scott’s DNA from a minor incident was accidentally reused in the rape case.

Then there’s the uncomfortable and inconvenient truth that any of us could have DNA present at a crime scene—even if we were never there. Moreover, DNA recovered at a crime scene could have been deposited there at a time other than when the crime took place. Someone could have visited beforehand or stumbled upon the scene afterward. Alternatively, their DNA could have arrived via a process called secondary transfer, where their DNA was transferred to someone else, who carried it to the scene.

But there is a DNA case that was (originally) puzzling. Actually, a whole bunch of DNA cases.

There is an interesting case, known as the Phantom of Heilbonn, that dates from 1993 in Austria, France and Germany. From that year the DNA of an unknown female was detected at crime scenes in those countries, including at six murder scenes, one of the victims being a female police officer from Heilbronn, Germany. Between 1993 and March 2009 the woman’s DNA was detected at 40 crime scenes which ranged from murder to burglaries and robberies. The DNA was found on items ranging from a biscuit to a heroin syringe to a stolen car.

Then it got really weird.

In March 2009 investigators discovered the same DNA on the burned body of a male asylum-seeker in France. Now this presented something of an anomaly: the corpse was male but the DNA was of a female.

You guessed it; it was the swabs themselves that were contaminated.

So a DNA match is just the start of an investigative process, but it could provide the investigative lead that eventually leads to the conviction of an individual.

Perhaps you’ve noticed that I use the phrase “investigative lead” a lot when talking about DNA and about facial recognition. Trust me, it’s important.

But is the taking of DNA at booking Constitutional?

Obviously this is a huge question, because technical ability to do something does not automatically mean that you are Constitutionally authorized to do so. There is, after all, Fourth Amendment language protecting us against “unreasonable searches and seizures.”

Is the taking of DNA from arrestees who have not been convicted (assuming state law allows it) reasonable, or unreasonable?

Alonzo Jay King, Jr. had a vested interest in this question.

Alonzo Jay King Jr…was arrested in 2009 on assault charges. Before he was convicted of that crime, police took a DNA sample pursuant to Maryland’s new law allowing for such collections at the time of arrest in certain offenses….

I want to pause right here to make sure that the key point is highlighted. King, an arrestee who had not been convicted at the time of any crime, was compelled to provide evidence. At the time of arrest, collection of certain types of evidence (such as fingerprints) is “reasonable.” But collection of certain other types of evidence (such as a forced confession) is “unreasonable.”

So King’s DNA was taken and was searched against a Maryland database of DNA from unsolved crimes. You won’t believe what happened next! (Actually, you will.)

The DNA matched a sample from an unsolved 2003 rape case, and Mr. King was convicted of that crime.

Sentenced to life in prison, actually.

Wicomico County Assistant State’s Attorney Elizabeth L. Ireland said she requested the court impose a life sentence on King, not only because of his past criminal convictions, but also because it turned out that he was a friend of the victim’s family. She said this proved King was a continuing danger to the community.

Before you say, “well, if he was the rapist, he should be imprisoned, legal niceties notwithstanding,” think of the implications of that statement. The entire U.S. legal system is based upon the premise that it is better for a guilty person to mistakenly go free than for an innocent person to mistakenly be punished.

And if that doesn’t sink in…what if YOU were arrested and convicted unlawfully? What if a plate analyzing YOUR DNA wasn’t cleaned properly, and you were unjustly convicted of rape? Or what if a confession were coerced from YOU, and used to convict you?

So King’s question was certainly important, regardless of whether or not he actually committed the rape for which he was convicted.

King therefore appealed on Fourth Amendment grounds, the Maryland Court of Appeals overturned his conviction (PDF), and the State of Maryland brought the case to the U.S. Supreme Court in 2013 (Maryland v. King). In a close 5-4 decision (PDF) in which both conservatives and liberals were on both sides of the argument, the Court ruled that the taking of DNA from arrestees WAS Constitutional.

But that wasn’t the end of the argument, because a new case arose in the state of California. But the California Supreme Court ruled in 2018 that the practice was allowed in that state.

So the taking of DNA at booking is not only authorized (in some states, for some charges), it’s also Constitutional. (Although the Supreme Court’s opinion is still widely debated.)

So anyone who gets arrested for a felony in my home state of California should be ready for a buccal (cheek) swab.

I’ve previously noted that the definition of “real-time” can vary depending upon the use case. In the automated fingerprint identification systems world of the late 1990s, a definition of “real-time” in minutes was appropriate, but for the computer aided dispatch world, “real-time” was (and is) measured in seconds.

“Hi, SCC folks, welcome to Printrak. You’re joining a company that sells REAL TIME AFIS that delivers results within one minute! Aren’t you impressed?”

“Hello, new corporate overlords. We provide computer aided dispatch systems that send police, fire, and medical personnel to crime scenes and emergency sites as soon as possible. If our CAD systems took AN ENTIRE MINUTE to dispatch personnel, PEOPLE WOULD DIE. We use really powerful computers to get personnel dispatched in a second. Enjoy your real time AFIS…amateurs.”

I also mentioned a two-hour “real-time” use case, which is (conservatively) the time it takes a rapid DNA instrument to do its work.

The rapid DNA vendors provide machines that can perform an automated DNA analysis in 90 minutes, a vast improvement over traditional DNA especially when existing backlogs are taken into account. And for the most part, 90 minutes is fine.

But the Surfside tragedy illustrates how 90 minutes may not be adequate.

There’s already been coverage of how rapid DNA can be, and is being, used to identify victims of the Surfside building collapse. NPR ran an article on this, and WFLA aired a news report.

To date I have not found a public source that lists how many rapid DNA machines are being used in the investigation, but let’s do a little math and see how many rapid DNA instruments could possibly be required.

Assume a conservative two hours is required to fully analyze each DNA sample and determine the possible identity of a deceased victim. Further assume that because of the importance of this case, the DNA instruments are being operated 24 hours a day, 7 days a week. No going home at 5:00 pm in this case, which is receiving international attention.

Now let’s look at the numbers. As of 2:00 pm Eastern Daylight Time today, 20 deaths are confirmed, and 128 people are still unaccounted for.

What happens if there is a sudden horrific discovery of 100 deceased? How long would it take to identify all of them?

If 3 rapid DNA instruments are available, and each is processing 12 DNA samples in a 24 hour day, then it would take about three days to run all the samples through the DNA instruments.

Three very long days for the families of the potential victims who are waiting for news.

So the authorities may need to move to plan B.

The Indian River County Sheriff’s Office has been notified it might be asked to respond with the agency’s rapid DNA test machines to the deadly condominium collapse in Surfside, Sheriff Eric Flowers said….

“They put our folks on standby last weekend to respond if theirs got overwhelmed,” Flowers said. “At this point, they’ve not called for that, but our folks are ready and our machines are ready that if they call us we will respond to assist in DNA identification.”

Yes, in this case you can throw more machines at a problem to solve it, provided that you have the proper personnel to support them. Luckily, the rapid DNA instruments themselves do not need a forensic background to operate them, since they are designed to operate in an automated fashion. However, if rapid DNA analysis has an inconclusive result, then additional traditional DNA analysis will have to be performed which will require forensic expertise. (That, however, is outside of the scope of this post.)

So where do we stand after Surfside?

Previous rapid DNA identification efforts have just involved one person or less than a dozen people. But this case, in which potentially over 100 people may need to be identified, is truly pushing the limits of the technology.

(Come to think of it, it’s similar to how video analytic analysis was pushed to the limits by the Boston Marathon bombings. But I digress.)

And sadly, there have already been instances in which that many people, or more people, needed to be identified. Imagine, for example, the crash of a large airplane. Or worse still, the crash of two large airplanes into a skyscraper.

And now this 90 minute response time suddenly doesn’t seem so fast any more.

Dr. Michael Bowers shared an article about DNA-ProKids.

From the article:

DNA-ProKids works with governments in Peru, Mexico, Guatemala, El Salvador, Paraguay, Thailand, Brazil, India and Malaysia….

The programme uses our unique genetic footprint to trace thousands of missing children around the world. Some have been stolen from their parents and trafficked for sex or as slave labour, others sold in illegal adoptions, and some lost in hospital mix-ups….

The article includes several stories, including one of a woman who was drugged and her baby taken from her.

Guatemala’s government, which uses the DNA-ProKids programme, contacted the police who were able to find the baby using DNA within 48 hours. The thief, who was wearing a mask because of the pandemic, could not be identified.

Read more here, or visit the DNA-ProKids website.