The Tabletop SEM and Forensic Science

My guest bloggers today are the ASPEX Team and they will discuss the Scanning Electron Microscope (SEM), a valuable forensic science tool. They also have a unique and fun offer for you. Want to know what things look like under the SEM? Maybe something in your own home? Now you can find out. Check out their site for some fun images and then if you want send them an item you want to scanned.

Ever wonder what something looks like up close? Really close? Most people have seen objects under a standard optical microscope, but few have seen what something looks like under a more powerful magnifying instrument: a scanning electron microscope (SEM). 

In forensics, crime scene samples are often very minute and difficult to decipher. SEMs provide verifiable evidence to the source of an object. These microscopes have the ability to reveal an item’s true topography and have become one of the primary methods in making arrests and defining crime scenes in the industry today. Items such as fibers, gun-shot residue and fingerprints are just a few of the many things that have been analyzed with a scanning electron microscope.

ASPEX, makers of the Personal Scanning Electron Microscope (PSEM), do not limit their analysis to only a microscope; rather, their packaged software allows the investigation to be viewed on a computer with different types of reports and tests available with the click of a mouse.

This, however, is only scratching the surface of all of the different ways scanning electron microscopes can influence the field of forensics and other areas.
In fact, ASPEX recently kicked off their “Send Us Your Sample” campaign, encouraging forensics professionals, science geeks, educators, students and anyone else who wants to send in samples to be scanned by an ASPEX tabletop SEM.

The PSEM has a scan range of 100nm to 5mm and an imaging resolution of 25nm, capable of bringing the smallest samples into focus. ASPEX will scan submitted samples and then post before/after photos along with an analytical report online. This allows viewers to see what the sample looks like to the naked eye as well as under the PSEM.

The SEM Image Gallery shows the samples already scanned, including mold, cat hair, fly eyes, an old toothbrush and more. Anyone interested in having an item scanned can simply fill out the submission form and send in a sample for analysis, free of charge.

The ASPEX Team

Thanks guys for being my guest today.

DPL

 

Chemical Ali Gets 4th Death Penalty

Saddam Hussein and his two miscreant offspring Uday and Qusay are no longer with us thanks to the US military. Good riddance. The world is a much better place without these three. But Saddam’s legacy lives on in the form of his cousin Ali Hassan al-Majid, affectionately known as Chemical Ali.

The good news is that Chemical Ali just received his fourth death sentence for crimes against humanity. The bad news is that he ever existed in the first place. Many of the Shiites and Kurds in Iraq can vouch for his horrific cruelty, which can only be compared to things such as The Holocaust perpetrated by Hitler’s minions, the killing fields of Pol Pot, the purges of Stalin, and, well, the list goes on and on. The inhumanity of humanity is sometimes bewildering.

Chemical Ali is responsible for the death of hundreds of thousands of people and these deaths were not pleasant. He employed a wide variety of chemicals such as Mustard Gas, VX, Sarin, and Tabun. Each of these is nasty in its own special way.

Mustard Gas first came to the public’s attention during the trench warfare of WWI. It literally burns the skin, first causing itching and swelling and ultimately large fluid-filled blisters appear over the body. If it affects the eyes it can lead to blindness. If it affects the lungs, as it typically does as the gas is inhaled, it can cause severe burning of the airways and lung tissue, causing the victim to literally drown in the fluids that are released after this type of injury. Even if the person survives the initial injuries, secondary infections often appear in the skin or the lungs and this in turn can lead to death.

Sarin gas is a fluorinated phosphonate that was originally used in insecticides but found its way into modern chemical warfare. It is classified as a cholinesterase inhibitor, which means that it interferes with the function of cholinesterase, a very important enzyme critical to neurotransmissions throughout the body. When exposed the victim will first feel a stuffy head and shortness of breath but very soon will develop chest pains, nausea, vomiting, excessive salivation, loss of control of bowels and bladder, diffuse twitching and jerking of the muscles, full-blown seizures, and finally coma and death. It’s not pretty. Even if the individual survives they can be left with permanent neurological damage. Sarin gas is as much is 500 times more toxic than cyanide.

Like Sarin, VX and Tabun are cholinesterase inhibitors and produce similar symptoms and are equally lethal.

These chemical agents are out there and available to the bad guys who don’t necessarily have our best interests at heart. Isn’t that a pleasant thought?

At least for now Chemical Ali is out of business and hopefully he will soon follow the Hussein Trio to wherever people like them go. I hope it’s a place filled with these very pleasant chemicals. Poetic justice being what it is.

 

Stupid Criminals: Stephfon Bennett

This will be the first installment of a recurring series that I am titling Stupid Criminals. There are a lot of them out there and when you hear about them sometimes you just have to shake your head. On 1-7-10, I posted the story of the less than clever serial killer LaMarques Devon McWilliams. He would easily fit into this category.

So would Stephfon Bennett.

It seems that Bennett and a couple of his buddies decided to pull off a robbery and they chose Daniel Martinez Batista and Diana Martinez as their victims. They approached them outside their apartment building and walked away with a wallet and purse. A successful outing for the larcenous crew. But apparently Bennett found Diana very attractive so he returned to the apartment to ask her out for a date. She of course recognized him as one of the robbers and the police were summoned and Bennett was hauled away.

Some people are just not bright enough to be successful criminals.

 

Doodling: A Low-Tech Lie Detector?

In my last blog post I discussed functional MRI and how it could be used to determine if someone was lying. Maybe. School isn’t out on that yet. Regardless, this rather high-tech lie detection method requires very expensive equipment and professional expertise to run the MRI machine and interpret the data. But Aldert Vrij of the University of Portsmouth in the UK may have come up with a clever, low-tech device.

He simply asked the question: Would a liar sketch a scene differently from someone who is telling the truth? To answer this question, he designed a very simple yet clever experiment. Using 31 volunteers, he sent them on a mission to collect a laptop from an actor who posed as a secret agent. Once they secured the laptop they were to deliver it to another agent at a different location. The second agent asked them to describe the scene where they received the laptop and to sketch it in detail. Previously half of the volunteers were told to tell the truth and the other half were told to lie about this event.

The results were interesting. Twelve of the 15 who told the truth sketched the scene and included the first agent in their drawing while only two of 16 liars included the agent. This was probably because they were recalling someplace that they knew well while they were making the sketch and since they knew that area without an agent being present they simply neglected to add him to the scene.

There was also a difference in perspective among the drawings. The liars tended to take a birds eye view in that they drew the scene from above much as if looking at a map. The truth tellers on the other hand drew the scene as they saw it from a first-person perspective. This makes sense since they were drawing what they actually saw while the liars were making up a drawing and therefore took a more global perspective.

This technique is undergoing further study and it will be interesting to see if it pans out. It would be very useful to have some low-tech and inexpensive way of determining whether someone was lying or being truthful.

 

The Brain of a Scam Artist

Oh, what a tangled web we weave…when first we practice to deceive.
Walter Scott

Scott’s famous quote seems to be prophetic on many counts. The whole tangled web thing reminds us of the tangle of neurons that make up our brain and practice, or at least foreknowledge, seems to be common among scammers and other liars. A recent study from the University of Zürich in Switzerland seems to underline this.

Are scam artist different from honest people? Do their brains function differently? Is there any signature left behind that would forewarn us that the scammer was less than truthful?

The Zurich study was conducted by Thomas Baumgartner and his colleagues and employed Functional Magnetic Resonance Imaging (fMRI)  to evaluate brain activity during deception. The research was folded into a game in which an investor was given real money and told to choose a trustee to invest the money with. They were told that giving the money to the trustee would increase their money but they courted the risk that the trustee was not obligated to share these winnings. The investor had to extract a promise from the trustee that he would indeed share the wealth. The other caveat here was that the trustee was not bound by his promise.

Virtually all of the trustees did indeed promise to share their winnings with the investor. Many of them followed through on their promises while others did not. Functional MRIs obtained during the promising episode revealed interesting results. In those who intended to break the promise certain areas of the brain showed increased activity. These were part of the prefrontal cortex and the amygdala system, both of which are involved with our emotions. This seems to reflect at least some degree of emotional conflict within those that lied. Those who followed through and kept their promise showed no increased activity in these areas.

Functional MRI showing increased activity in certain areas of the prefrontal cortex and the amygdala

The entire field of brain scanning to determine whether someone is telling the truth or lying is a rapidly growing field. Since the standard polygraph, or lie detector, is fraught with problems and for this reason is not admissible in court, there has always been a search for a better method of determining if someone is lying or not. The area of brain scanning, whether a functional MRI, CT scanning, or functional PET scanning, has been the subject of research and controversy. It will be interesting to see as the years go by if any of these prove to be useful and reliable.

 

Succinylcholine: Is It the Perfect Murder Weapon? Not Exactly.

Succinylcholine, SUX for short, is a neuromuscular paralytic drug. This means that it works at the junction of the nerves and muscles and causes muscular paralysis. It paralyzes all the muscles of the body, including those used for breathing. Without ventilatory support anyone who receives this drug will die from asphyxia. The bad news is that they will be wide awake while this occurs because SUX causes muscular paralysis but has no sedative effects.

In medicine, it is used as part of anesthesia. Since it causes complete muscular relaxation it makes passing the endotracheal (ET) tube much easier. This ET tube is passed through the nose or the mouth and into the trachea where a balloon is inflated to keep it in position. The tube has been used to ventilate the patient throughout the surgery.

Succinylcholine, or some similar paralytic agent, is part of the three drug cocktail used in lethal injection executions. The first is a sedative to put the person to sleep, the second is the paralytic drug that paralyzes all muscles, and the final is potassium chloride which immediately stops the heart.

Succinylcholine must be injected and it works very quickly—within seconds to a minute. It is very short acting because enzymes in the body begin to break down the drug almost immediately. This makes it tough for the crime lab. There is no Succinylcholine left to test and so testing for it will prove negative. However testing for the breakdown products, also called metabolites, of the drug has proved successful in many cases.

The ability to test for these breakdown products stemmed from the case of Carl Coppolino, one of F. Lee Bailey’s most famous cases. This case is a milestone in Forensic Toxicology.

The Carl Coppolino Case

Carl Coppolino and his wife Carmela were both physicians, who moved from New Jersey to Longboat Key, Florida. On the night of August 28, 1965, Carl called his friend Dr. Juliette Karow and told her he had found his wife dead of an apparent heart attack. Dr. Karow came to the Coppolino home, agreed with Carl’s assessment, and ultimately signed Carmela’s death certificate, stating that her death was due to a coronary thrombosis. The Sarasota County Medical Examiner also agreed so no autopsy was performed.

Slightly more than a month later, Carl married wealthy socialite Mary Gibson, which angered his neighbor Marjorie Farber. It seems that Marjorie and her husband knew the Coppolinos in New Jersey. In fact, Marjorie and Carl had been having an affair. After the death of Marjorie’s husband William and Carl’s move to Florida, she followed the Coppolinos to Florida so she could continue her relationship with Carl.

Marjorie visited her friend Dr. Karow and told her that Marjorie’s husband’s death back in New Jersey had not been the natural event everyone thought. She said that Carl, who was an anesthesiologist, had given her a syringe filled with a liquid and instructed her how to inject her husband with it. Her attempt was only partially successful and she managed to inject only a small amount of the drug into her husband. She panicked and called Carl who came over and finished off William by strangling him. Carl returned home and then Marjorie called the Coppolino’s home, saying that her husband had died of an apparent heart attack. Ironically, Carmela had gone to Marjorie’s home and as a physician had pronounced William Farber dead and signed his death certificate, stating that his death was due to coronary thrombosis.

After Marjorie’s revelations, an investigation into both deaths followed with New York Chief Medical Examiner Dr. Milton Helpern performing an autopsy on each of the victims. Attorney F. Lee Bailey managed to gain an acquittal for Carl on the death of William Farber, but the interesting case was that of Carl’s wife, Carmella. Halpern was well aware that Carl was an anesthesiologist and guessed that he might have access to many anesthetic drugs, including the muscle paralytic drug succinylcholine, which at that time was essentially impossible to find in a corpse. Dr. Halpern brought toxicologist Dr. Charles Umberger into the case. After months of research, Umberger finally managed to isolate some of the metabolites of succinylcholine, one of which was succinic acid. He then found large quantities of this acid in the brain tissues of Carmela Coppolino. Carl was convicted of second-degree murder.

There have been many other famous cases in which Succinylcholine was employed or at least suspected to have been used. Here are a couple of interesting ones:

Genene Jones

Kathy Augustine/Chaz Higgs

 

LaMarques Devon McWilliams: Not the Smartest of Serial Killers

When you think of serial killers you think of fictional characters like Hannibal Lecter or real-life killers like Ted Bundy. Both were smart and clever and got away with their deeds for many years. But are these killers really smarter than the rest of us or are they simply lucky? In truth, it’s often a little of both.

Take the case of LaMarques Devon McWilliams. For years the police in Houston Texas had been trying to trap a serial killer that was known as the Acres Homes Killer, a moniker hung on the killer because he had killed six prostitutes in the Acres Homes area of Houston. The police were baffled and had few leads.

Their break came when McWilliams got stupid. He apparently abducted another woman, placed her in the trunk of his car, and headed off to an area where he could rape and kill her. Unfortunately for him, his car became mired on a muddy road and he was unable to free it. So in his infinite wisdom, he forced his would-be victim to help him. He released her from the trunk, put her behind the wheel of a car, and he pushed from behind. This worked. The car worked free of the mud. Unfortunately for McWilliams, the woman simply drove away, leaving this brilliant serial killer standing in the mud.

McWilliams was arrested and his DNA was obtained and sent to the FBI lab. It took only 48 hours to match his DNA profile to that of the Acres Homes Killer.

As the great philosopher Forrest Gump said: “Stupid is as stupid does.”

 

Alcohol Poisoning: A New Record

We have a winner! A new blood-alcohol content (BAC) champion.

The legal limit for BAC in most states is 0.08%. Below that you get to walk and above that you get to wobble yourself to jail. In general, and this varies greatly from person to person, a level below 0.04 causes little effect, while between that level and 0.08 some loss of judgment and coordination occurs. This becomes even more pronounced with a level up to around 0.12 to 0.15 or so. These people typically appear intoxicated. If you go higher to a level above 0.20, you might be considered sloppy drunk. And a level above 0.40 can be lethal.

There is a term in medicine and forensics known as the LD50, which stands for the Lethal Dose 50%. This simply means that if you give 100 people this dose of a drug, 50 will die. In the case of alcohol this amount results in a BAC of around 0.40%. Anyone who drinks this amount of alcohol has a 50% chance of dying. Of course statistics such as this are only important to the masses since own individual level it’s either 0% or 100%. You either die or you don’t.

Enter our champion. It seems that on December 1, 2009, Marguerite Engle was found sleeping on the side of Interstate 90 in South Dakota. The South Dakota Highway Patrol stopped to investigate and found Marguerite asleep in a stolen van. She was arrested and toxicological examinations were done. Her blood-alcohol level came back at 0.708. Nearly twice the lethal level and nine times the legal limit in South Dakota. The previous record for South Dakota is believed to be 0.56. Marguerite shattered that record.

This brings up two points. The first is, you can’t kill a drunk. A drunk driving a tiny, underweight hybrid can slam head-on into a family of four in a massive SUV and the family will be killed while the drunk walks away. Happens all the time. Ask any ER doc and he will agree. Fortunately, Marguerite Engle didn’t kill anyone.

The second point is that poisons and drugs are unpredictable. What can kill one person may not kill the other. What can harm one person may go unnoticed by another. Obviously Marguerite can handle alcohol whole lot better than the average Joe.

Rapid City Journal Article