Tag Archives: Investigation

GENOMICS — THE FUTURE OF FORENSIC DNA PROFILING

A3Genomics is the scientific study of the molecular instructions encoded in your cells.  It maps your entire genetic structure. Till now, forensic science has focused on only identifying your cell’s nuclei signature — your inner DNA (deoxyribonucleic acid) and, to a degree, your outer miDNA (mitochondrial DNA) — not your genes. The old method of forensically profiling your biological fingerprint by DNA analysis is being replaced by a computerized 3D genome recreation of your entire being.

A17Genomics is a concept first developed in the 1970’s. It led to the Human Genome Project (HGP) being completed in 2003. The HGP was a massive international research venture that sequenced and mapped all of the human cell genes — together known as the genome. The HGP gave us the ability to read nature’s complete genetic blueprint for building a human being. Like you.

So what’s a genome?

A14A genome is the whole ensemble of your genetic material. It’s the molecular guide of your DNA, your chromosomes, and your genes that tells how to make your cells. It’s the instruction manual for your body. That book is your genome and the study of that book is termed genomics. It’s pretty much a math exercise. And it’s deadly stuff for identifying criminals with.

Let’s take a quick look at your biology.

A35Deoxyribonucleic acid is the chemical compound that contains the instructions to develop and direct your life as an organism. DNA molecules are made of two twisting, paired strands, often referred to as a double helix.

Each DNA strand is made of four chemical units, called nucleotide bases, which comprise the genetic “alphabet.” The bases are adenine (A), thymine (T), guanine (G), and cytosine (C). Bases on opposite strands pair specifically — an A always pairs with a T — a C always pairs with a G. The order of the As, Ts, Cs, and Gs determines the meaning of the information encoded in that part of a DNA molecule. It’s just like the order of letters determine the meaning of a word, only DNA is written out in a barcode locus.

Every single cell in your body contains a complete copy of the 3.2 billion DNA base pairs, or letters, that code your human genome.

DNA’s four-letter language contains information needed to build your physical body. A gene refers to the unit of DNA that carries the instructions for making a specific protein, or set of proteins, and there’s 23,000 genes in your genome code. Each gene directs an average of three proteins.

A11

If you could peer inside your cells, you’d see your genome contained in 46 tightly packed bundles of DNA — 23 came from your mother and 23 from your father. These DNA bundles, called chromosomes, provide instructions that enable a one-cell embryo to develop into a 100 trillion-cell adult. So, every time the human body produces a sperm or an egg, 3 billion DNA letters must be copied and packaged so they can be passed along to future offspring.

A31Humans come in many shapes and sizes, but we’re all very similar at the DNA level. In fact, the genomes of any two people are more than 99% the same. Still, the tiny fraction of the genome that varies among humans is critical when it comes to forensically identifying a particular individual. DNA variations are part of what makes each of us unique, but it’s in the genes that the real difference lies. They direct what you look like.

Okay. Enough of the biology lecture. How is genomics gonna catch some crooks?

It’s not just genomics. Science now has a great handle on how your DNA is formed and how your genes fine-tune your uniqueness. The problem has been in how to process a staggering forensic workload that has bottlenecked the crime labs and the courts — and how to put a face and a name to an unidentified DNA profile..

A26The answer lies in genomic computerization. The good news is that technological progress is being made faster than anyone ever dreamed possible. Now the labs are looking at your entire genome package for identification, not just at that little bit of nucleic or mitochondrial DNA which is dirty, volatile, and time-consuming stuff to process.

Advancements in computerized processing are allowing crime labs to build an entire picture of you as a suspect — not just an impersonal, academic graph of the matching points in either your biological evidence sample that you left behind at the scene, or your known reference sample that investigators obtained from you.

A2Think about how many cold cases there are where the investigators have a clear DNA profile of you as the perpetrator, but they have absolutely no clue what you look like. They have no idea whether you’re young or old, black or white, have green eyes or brown. They don’t know your hair color or texture. They don’t know if you’re tall or short. And, in some cases, they don’t know if you’re male or female.

Genomic profiling is going to change the game. Computers will speed it up. 

A25Illumina Corporation of San Diego is a world leader in Forensic Genomic technology. They’ve developed a process called Next Generation Sequencing (NGS) that can simultaneously analyze every locus-point in a traditional DNA barcode using less than 1 nanogram of a sample in a fraction of traditional turn-around time that it’s currently taking.

Illumina is also at the forefront of developing the new cornerstone of contemporary forensic science — being able to generate a physical description of the DNA’s donor based on their genome profile.

A22Think about the ramifications. It’s not only going to assist in solving current cases. It’s going to give a physical look at the perpetrators of cold cases. Identify found remains with no names. Help in sorting disaster victims. And make accurate aging estimations for missing children.

The speed and accuracy of forensic genomic profiling will have far reaching effect on the costs in the criminal justice system. Faster and higher rates of identification will remove more dangerous offenders from society and the reliability of their forensic identifications will result in less trial time. It will reduce investigator workload in chasing blind leads. And it will, undoubtedly, save lives.

A29I think we’re in a fascinating time, watching technological advancements in forensic sciences. Genomic profiling is a fantastic breakthrough. We’re close to the day when your tiny biological dropping at the scene of your crime will go into a machine, the button pressed, and not just will your virtual mugshot come out — it’ll build a full-color, 3D image of your entire person right from your molecules to your moles.

Yes, science has come a long, long way in understanding how your human genome instruction book is written.

God knows who wrote it.

FORENSIC BLOODSTAIN PATTERN ANALYSIS

AA43Bloodstain Pattern Analysis is the forensic interpretation of human blood evidence in crime scene investigations. It’s used to recreate actions that caused the bloodshed. Because blood has chemical properties that behave according to specific laws, trained analyists can examine the size, shape, and distribution of bloodstains to draw conclusions of what did—or did not—happen.

Bloodstain Pattern Analysis (BPA) applies the sciences of anatomy, biology, chemistry, mathematics, and physics to answer questions like:

  • Where’d the blood come from?
  • Who’d it belong to?
  • How’d it get there?
  • What caused the wound(s)?
  • From what direction was the victim assailed?
  • How were the victim and perpetrator positioned?
  • How many victims and perpetrators were there?
  • What movements were made after the bloodshed?

AA24You’ve seen the CSI shows where investigators, dressed in their ‘bunny suits’, photograph drops, streaks, smears, and pools of blood, then swab for DNA and String the room back to Area of Convergence points. Well, that’s pretty much how it happens, except today most Stringing is done by 3D computerization.

Bloodstain pattern interpretation is nothing new. It’s been around two hundred years and became increasing sophisticated as technology advanced. I’ve been involved in a number of BPA examinations during my time as a cop and coroner. One that really stands out was when Billy Ray Hennessey axe-murdered his ex-girlfriend and her new lover. The room looked like a bomb went off in a red paint factory. I’ll tell you more about it at the end of this article. First, let’s look at how blood behaves.

Blood has three components that are suspended in plasma.

AA25Erythrocytes are your red cells that transfer oxygen through hemoglobin. It’s what gives blood the red color. Leukocytes, your white cells, are your body’s defenders and support your immune system in fighting infection and disease. Platelets are formed in your bone marrow and play a major role in hemostasis, or plugging up breaches in vessels.

Blood composition is about 55% plasma and 45% formed elements, or cells, which remain suspended due to agitation caused by your circulatory system. That’s called viscosity—it’s density or internal friction. Once blood leaves your body’s pressurized containment, it’s subject to the forces of gravity and surface tension which dictates its resting shape. That can be in drops, streaks, or pools.

Crime scene bloodstains take different forms due to factors like velocity and distance of travel, amount of blood flow, angle of impact, and type of surface or target it lands on. There are eight categories of bloodstain patterns:

AA26Single Drop – These stains are typically from a vertical fall and under low velocity, like when your cut your finger and blood drips to the floor. Blood molecules are very cohesive. They attract and bind in a surface tension that makes a sphere. The drop stays in a ball until it strikes an object or a force acts on it. This is called bleed-out.

AA21Impact Spatter – These result from forceful impacts between an object and wet blood, causing the blood to break into little droplets. Greater force produces smaller droplets. The study of impact staining provides huge insight into the relative positions of individuals and objects involved in the crime. There are three sub-categories of impacts:

  1. Low Velocity Impact Spatter (LVIS)

AA4Also called Passive Impact Spatters, these are the largest bloodstain drops with a diameter of 4mm or greater. They travel at a slow speed, no greater than 1.5 m/s. They’re associated with being struck by a large, blunt instrument such as a chair or leaking from an open wound. They’re also formed when a large amount of blood has been transferred to another surface and the excess drips down.

  1. Medium Velocity Impact Spatter (MVIS)

AA1These spatters are associated with an intense beating like from a club, a hammer, a gun butt, or a bag of frozen pork chops. (Yes, I once had a homicide case where a guy’s head was caved-in with a bag of frozen pork chops.) MVIS drops are less than 4mm and get propelled at speeds between 1.5 and 7.5 m/s. The further from the target surface that blood is expelled, the larger the drops will be.

  1. High Velocity Impact Spatter (HVIS)

AA2This stain pattern is caused by gunshots, explosions, or contact with high-speed objects like having your throat cut with an electric carving knife. (Had one of those, too.) They’re evident by masses of tiny droplets less than 2mm in diameter and occur at velocities far in excess of 7.5 m/s. There’s no mistaking this type of bloodstain. The angle of impact is evident by an elongated shape – the longer the stain, the longer the angle from vertical.

AA19Cast-Off Stains – COS are common in scenes such as Billy Ray Hennessey’s axe-murders where straight and curved lines of blood are made on the walls and ceiling by the centrifugal force of back-and-forth swings. They produce tear-shaped or oblong stains with ‘tails’ that point in the direction of travel. By reversing the line of travel, the path can be traced or stringed to its area of convergence.

 

AA18Transfer Bloodstains – These are generally patches and smears of blood deposited secondary to the main, violent event. They say a lot about sequence. It can be when a victim tried to crawl away, the body was dragged, the perpetrator placed a bloody hand on a wall, or when he hid the axe in a closet like Billy Ray did. Tell you more about him soon.

AA20Projected Pattern – This is from arterial damage, such as severed carotids, femorals, radials, and brachials where pressurized blood ejaculates via the still-beating heart. You’ll see groups of big to small splotches, usually in an arc pattern. Very common in stabbings.

Pooling – Usually occurs once the victim is unconscious and passively exsanguinates. That’s the fancy term for bleeding to death. Something telling to a Bloodstain Pattern Analyst is where large pools of blood occur in different locations—no doubt the body’s been moved.

AA28Insect Stains – Not long after death, the bugs show up. They land in the bloodstains and make little tracks all over the place. These are easily confused with HVIS to the untrained eye and known in the industry as Flyspeck.

Expiration Stains – These are incidental bloodstains associated with injuries to the respiratory and abdominal tracts where a gasping victim expels through the mouth or nose. They appear diluted, more brownish in color due to mixture with saliva or mucous, and look like a fine mist.

Examination of a bloody crime scene is a slow and methodical procedure.

AA3The area is still-photographed from wide, medium, and close-up angles as well as videoed. Each stain pattern is marked, catalogued, and a swab taken for serology or DNA typing. The patterns are then Strung to their Point Of Origin, or area of convergence, and a complex application of trigonometry begins to tell a compelling tale of just what went down.

The visual absence of blood can be misleading.

Criminals occasionally clean up a scene or there may be only a small bit of blood emitted. Chemical reactive agents like luminol and phenolphthalein can be applied which visualize latent stains. Light spectrum tools, such as LumiLights, are also used to amplify spots not visible to the naked eye.

AA40Getting back to Billy Ray Hennessey — This guy hid in his ex’s attic with an axe for two and a half days, waiting to catch her screwing a new beau. Sure enough, she brought one home from the bar. At 3:00 am, Billy Ray crept down from the hatch, snuck into the bedroom, and chopped them to pieces. Like I said, the crime scene looked like a bomb exploded in a red paint factory.

It took us three days to catch Billy Ray. He did the right thing and fessed-up, then reenacted the murders on video. It was the coldest thing I’ve seen. Billy Ray described what he did as if he were watching Jason or The Shining, going through repeated motions of chopping, and back-swinging, and chopping some more. He demonstrated with a 2×2 stick as a prop. (We were nervous about giving him a real axe.) He showed how he modified body positions after death, where he hid his axe in the closet, and where he cleaned himself up.

Billy Ray did the right thing again. He pleaded guilty, receiving two life sentences.

AA30During the three days that we hunted for Billy Ray, the Forensic Identification team had sealed the crime scene and independently conducted their Bloodstain Pattern Analysis. Once Billy Ray was done, we (the detective team) compared notes with the forensic team and — unbeknownst to what Billy Ray reenacted — the forensic folks got it bang-on. They’d reconstructed how many blows each victim received, various positions everyone was in, and… who fought back.

I’ve been sold on the science ever since.

*   *   *

Here links to more information on Forensic Bloodstain Pattern Analysis:

A Simplified Guide To Bloodstain Pattern Analysis

The Forensics Library – Bloodstain Pattern Analysis

Principles Of Bloodstain Pattern Analysis – Theory and Practice

Bloodstain Pattern Analysis – Crime Scene Reconstruction

CAN YOU BEAT THE POLYGRAPH?

A1The polygraph, or lie detector, is a forensic investigative tool that’s used as an aid to verify the truthfulness of a person’s statements. Polygraph examinations— properly conducted by trained professionals on competent subjects with a clear issue— are remarkably accurate, but they’re not foolproof. Yes. They’ve been known to be beaten. The question is—can you?

Polygraph examination interpretation is not admissible as evidence in court. They’re not a replacement or shortcut for a proper investigation and a thorough interview of the subject. Statistics show that the majority of people who undergo polygraph examinations are found to be truthful. Perhaps the term Lie Detector should be replaced with Truth Verifier.

A3In my policing career, I’ve been involved in well over a hundred polygraph examinations, including getting hooked up myself for a test drive. (Turns out I’m a terrible liar—not sure how I’m gonna make out with this new career as a fiction writer.) The subjects I’d had polygraphed were a mixture of suspects, witnesses, complainants, and victims. I’d say that sixty percent of the subjects were truthful, thirty percent were lying, and ten percent were inconclusive.

It makes sense, when you think about it, that the majority are truthful because they know it will work to their advantage. I can’t think of the number of times I’ve had subjects refuse to take the test, giving excuses everywhere from “Those things are rigged to frame me” to “I heard you get testicle cancer from it”.

Before giving you some tips on how to pass a polygraph when you’re dead-ass lying, let’s look at what the thing is and how it works.

A2The word polygraph comes from the Greek word polugraphos which means “to sniff-out bullshit”. (Go ahead—call me a liar). Polygraphs have been around since the 1920s and have evolved from clunky paper-reel with ink-pen devices to modern laptops with automated scoring systems. Clinically, the process is known as psychophysiological detection of deception.

The instruments are a combination of medical devices that monitor a subject’s physiological responses to a set of questions designed to put the subject under the stress; the stress associated with deception. The involuntary bodily functions include heart rate, blood pressure, respiration, galvanic skin conduction, and perspiration.

A4Polygraphic theory dictates that a subject will show a spike in some, or all, of these functions when asked a question and forced to knowingly lie. In a criminal investigation, the examination questions are formed between the polygraphist and the subject during an extensive pre-test interview.

There are four categories of questions—all must be answered  “Yes” or “No”. Three categories are control questions and one is issue questions.

Category One is where the subject conclusively knows they’re truthful:

Q — Is your name Garry Rodgers?  “Yes”
Q — Are you a retired police officer?  “Yes”
Q — Did you make the Amazon Top Ten list? “Yes”

Category Two is asking the subject ambiguous questions:

Q — Is there life after death?  “Yes”
Q — Did the chicken come before the egg? “No”
Q — Are you going to make the Top Ten list again?  “Dude, let me tell ya…”

Category Three has the subject intentionally lie:

Q — Were you kidnapped by aliens?  “Yes”
Q — Did you ever ride a camel?  “No”
Q — Are you going to try make the Top Ten list again?  “No”

Category Four deals with the issues:

Q — Did you murder Jimmy Hoffa?  “No”
Q — Do you know who murdered Jimmy Hoffa?  “No”
Q — Did  murdering Jimmy Hoffa help you get on the Top Ten list?  “It’s not how it looks…”

A7Only “Yes” or “No” answers are acceptable during a polygraph examination because the issue has to be clear in the subject’s mind. Black and White. All clarification is worked-out in the pre-test interview. The subject is never surprised by the question, but the question order is completely unknown. This creates an atmosphere of anxiety as the subject waits to hear the questions that really matter.

The biggest concern that I’ve heard from people who are asked to submit to a polygraph is “What happens if I’m nervous?”

A8This is expected. Anyone, police officers included, would experience anxiety when being examined. Part of a polygraphist’s skill is to build a rapport with the subject and put them at relative ease before the questioning starts. One of the reasons in building this rapport is to get the subject to volunteer information that the investigation hasn’t uncovered. I’ve seen subjects give critical facts because the right questions weren’t asked during the investigation and I’ve seen subjects fall apart and confess before being strapped into the chair.

The key to successful polygraph examinations is the skill of the examiner. The polygraph is just a tool—an extension of the examiner’s mind and voice.

A6So — given there’s proven science and skill behind polygraphs — how can you beat one?

Like I said, given a professional examiner, a competent subject, and a clear issue, polygraph results are remarkably accurate. There’s always exceptions and here’s some tips on how to pass the graph.

  • Prepare well in advance.
  • Research and understand the process so you won’t feel oppressed. The examiner will take every advantage of your ignorance.
  • Know the issue(s) and know what the examiner is looking for.
  • Talk to someone who has experienced a test.
  • Approach the test as an extreme job interview. ‘Dress for the job’. Arrive on time. Sober. Rested. Do not reschedule. Make a good first impression.
  • Know that you’re going to be video recorded.
  • Understand the test starts right when you arrive and ends when you leave. It’s not just the time you’re hooked to the machine.
  • Be on guard. There will be trick questions in the pre-test. It’s part of the process.
  • Listen carefully to what the examiner says and respond accordingly. Do not try and monopolize the conversation.
  • The examiner is not your friend, despite how nice she comes across in the pre-test. Her job is to get to the truth. Remember—you’re dealing with a highly trained professional who knows psychology. If her exam shows you’re deceitful, she’ll go for your jugular in the post-test.
  • Recognize the relevant and irrelevant control questions. Focus on what’s relevant and do not offer more information than what’s pertinent to the issue.
  • Play dumb. Don’t try to impress the examiner that you’ve studied up. You’ll only look stupid.
  • Breathe normally. Shortness of breath naturally triggers the other body functions to accelerate and it will increase nervousness.
  • Take lots of time to answer.
  • Think of something mentally stressful when answering a control question—like the time when you were a kid and your dog was hit by the train. That will raise the ‘normal’ graph peaks.
  • Think of something calming when answering issue questions—like getting a new puppy. That will flatten stress peaks.
  • Keep your eyes open during the questions. The examiner will ask you to close them because this significantly alters your sensory awareness and puts you at a disadvantage. This is very important.
  • Bite your tongue during every question except the truthful control ones. This levels the playing field.

So, who’s got away with taking a lie detector?

A10I call her The Mother From Hell. I investigated a bizarre case of Munchausen Syndrome by Proxy—a rare form of child abuse where a parent causes harm to their child to bring attention to themselves. This woman repeatedly complained that her infant daughter was choking, then was caught by hospital staff with her hands on the girl’s neck. She denied it. We polygraphed her. She blew the needles off the machine and confessed. The Mother From Hell got off in court because they ruled her confession inadmissible due to it being elicited under oppression from the polygraph examination.

A12Gary Ridgway, The Green River Killer from Seattle, strangled over fifty women in the 1980’s. He was on police radar early in the serial killing investigation, ‘passed’ a polygraph, and got warehoused as a suspect. He went on to kill many more before being caught on DNA.

Can you beat the polygraph?

The best advice I can give is don’t take one.