Gut Feeling

This is my last blog of 2012, and as it is the festive season, I'm going to write about intestinal micro-organisms!

 

We humans live with a large population of micro-organisms in our intestines.  Collectively known as gut flora, they perform a variety of useful functions, such as extracting nutrients from food, training the immune system to respond only to pathogens and preventing the growth of harmful bacteria.

Now, researchers at Washington School of Medicine in St Louis and the European Molecular Biology Laboratory in Heidelberg, Germany, are suggesting that our gut flora may have an important part to play in forensics.  Just as our DNA varies from person to person, so, apparently, does the DNA of the micro-organisms in our intestines.  This means that a person may be identifiable from the DNA profile of their gut flora.

Here is an account of the research:

New Genetic Fingerprint lives in your Gut

Clearly, the overall purpose of the research is to improve human health.  But advances in forensics often come from unexpected sources.  The revolutionary approach to developing invisible indented impressions of writing on paper arose, almost accidentally, from research into latent fingerprint development techniques.

So, if one of your characters leaves a series of anonymous letters smeared in excrement in a number of other characters' mailboxes (it does happen), maybe this new technique could provide a starting point for the police investigation.  Just a thought.........

If you celebrate Christmas, have a wonderful time and don't treat your gut flora too badly!  Thank you for reading my blog this year, and  I hope to connect with you again in 2013.

Don't forget to follow me on Twitter @forensicswrite.



The Sole Evidence

On 27th July 2008, at approximately 5am, newlyweds Ben and Catherine Mullany were shot and robbed in their hotel bedroom on the last day of their Antiguan honeymoon.  Catherine died instantly; Ben went into a coma and survived long enough to be flown home to Wales, but doctors could do nothing for him.  A week later, his life support machine was turned off. 

Two weeks after the Mullany killings, local shopkeeper Woneta Anderson was shot and killed during a robbery at her store.  All three victims had been shot once in the head. 

The Government of Antigua and Barbuda had called in London's Metropolitan Police to assist with the investigations into the Mullany killings.  Antigua's tourism-based economy was likely to be severely damaged by the killings, unless the case was solved quickly.  Moreover,  Antigua had only one trained forensics officer, who would be under immense pressure without additional expert assistance.   

The Mullany killings were found to be linked to the Anderson killing - all three victims were shot with the same gun.  From the wealth of forensic evidence found at the Anderson crime scene, two local men, Kaniel Martin and Avie Howell, were arrested and subsequently charged with murder. 

After a trial lasting two months, Martin and Howell were convicted of the three killings.  Each man received three consecutive life sentences for their crimes.  At the time of their sentencing, they had yet to be tried for two other charges of causing death by shooting.

One important piece of forensic evidence concerned the partial shoeprints made in blood, which were found at the scene of the Anderson killing.  The forensic examination of shoeprints is a huge subject and impossible to cover in detail in a blog post.  However, here is a report of the shoeprint evidence given at the Mullany/Anderson murder trial, which, I think will give you a good general overview of the topic.

 Shoeprint evidence at Mullany/Anderson murder trial

As is clear from Anthony Larkin's evidence, in order to be able to link a suspect's shoe with a crime scene sole impression, individual features have to be present in both.

Individualisation of a shoe's sole is based upon the knowledge that accidental marks formed during wear are unique.  It is essential that the forensic examiner is well-versed in the shoe manufacturing process, otherwise manufacturing defects could be mistakenly identified as unique wear damage, particularly by an inexperienced examiner.  Cheap footwear is more likely to contain manufacturing defects than expensive brands. 

The surface bearing the shoeprints can affect the quality of the impression.  The wooden floor of Woneta Anderson's store was rough and uneven.  As Mr Larkin pointed out, the damage feature on the sole impression was not as clear as it could have been, because of problems with the surface of the floorboards.

Since footwear impressions are one of the most common types of evidence found at a crime scene, a great deal of research has been carried out to find the best methods for enhancing visible shoeprint impressions and developing latent (invisible) impressions, particularly on difficult surfaces, such as clothing.

Researchers at the University of Abertay in Scotland have recently produced 'the world's first detailed images of latent footwear left on fabrics'.  By adapting and modifying existing visualisation techniques, the researchers hope that their methods will be particularly valuable in cases where no DNA or fingerprint evidence is found.

Read about their work here:

 Shoeprints recovered from crime scene clothing

Finally, a word about automation.  Clearly, the linking of a crime scene shoeprint with an item of footwear is always a task for a forensic expert.  However, reference databases of footwear sole patterns are available for the police and other law enforcement agencies to allow them to identify makes and styles of footwear.  This obviously saves a lot of time and allows a case to move forward more rapidly.

Here are some examples of commercially available shoeprint identification products.

Foster and Freeman's shoeprint identification products

Cape Coral PD in Florida found its shoeprint matching software invaluable in tracking down a serial burglar.  Watch the video here:

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The Scent of Death

Last year, the USA was gripped by the Casey Anthony murder trial.  Anthony was accused of murdering her daughter, Caylee, aged 2, and providing false information to the police.  Caylee was not reported missing for a month, and it was a further 6 months before her decomposed remains were found in woods close to her home.  When the jury reached a 'not guilty' verdict on the murder charge, the country was shocked.  There had not been such a controversial verdict since OJ.  I'm sure you will have your own opinions about both verdicts.

 

One of the prosecution witnesses at the Anthony trial was K-9 Deputy Jason Forgey, whose cadaver dog, Gerus, alerted to the scent of human remains in the trunk of Casey Anthony's car and a corner of her parents' back yard.

Watch Deputy Forgey's testimony here.     

The ability of dogs to locate people and objects by scent has been utilised by law enforcement agencies for a long time.  Trained dogs are used primarily for tracking, searching and locating evidence.  Some dogs are cross-trained for more than one task; others are trained to perform a specific function.

There seems to be some variation in terminology for describing and differentiating between dogs trained for particular tasks, but for the purposes of this blog, I'm using the term  'Cadaver Dogs' to describe dogs which are primarily trained as search dogs, but have also received cross-training in the location of dead human bodies.

By contrast, 'Forensic Evidence Dogs' (also known as 'Human Remains Detection Dogs'), specialise in buried bodies, old homicide cases, bone searches, buildings searches, vehicle searches, crime scene searches, small scent sources and residual scent.  Other forensic evidence dogs specialise in searching for firearms, explosives or drugs.

In forensic work, the breed of dog is less important than its ability to learn, interact with its handler and locate a particular scent.  But a search and rescue dog, for example, needs to be robust, like a German Shepherd.

Both Cadaver Dogs and Forensic Evidence/HRD Dogs are trained to locate the scent of death, which is caused by chemical decomposition.  However, because they are not cross-trained, Forensic Evidence/HRD Dogs are never looking for live scent.  They have been taught to exclude fresh human scent and to ignore all animal scents, whether fresh or decomposed, when carrying out a search.  

Working slowly and methodically, a fully trained Forensic Evidence/HRD Dog will not disturb a crime scene nor will it retrieve evidence.  It will also search homes and vehicles without causing any damage.  When it finds a residual scent of a dead human or dried blood, for example, it will alert its handler by demonstrating a particular behaviour, such as standing still and barking, or lying down.

The scent may not indicate the actual location of the remains.  Running water can move the scent away from the grave site.  So although the dog will alert where the scent is strongest, this may be some distance from the body itself. 

The handler of a Forensic Evidence/HRD Dog also has to be highly trained.  If called to court, the handler has, in effect, to testify on behalf of their dog.  So handlers log all their dogs' training and also take courses in orienteering, criminal procedures, report writing, hazardous materials awareness and canine first aid.

So how accurate are Cadaver Dogs and Forensic Evidence/HRD Dogs?  Canine fallibility was alluded to in Deputy Forgey's cross-examination. 

Various studies have shown that handler error and inexperience can lower the recovery success rate from 100% to as little as 57%.  It doesn't matter how good the dog is at locating evidence, if the handler is unable to interpret the dog's alerts properly.

Just like a human, a tired, hungry or stressed dog will not perform as well as when it is fresh, fed and happy.  In fact, a severely fatigued dog may give a false alert, simply because it wants to rest.

Forensic Evidence/HRD Dogs are also employed away from law enforcement work. The Institute for Canine Forensics has been using Forensic Evidence/HRD Dogs to search for Native American burials and cremations on the site of the proposed Tule Wind Energy site in the McCain Valley, California.

Here is a video of one of the dogs at work.
       

Don't forget, you can find out when I post a new blog  - and much more - by following me on Twitter @forensicswrite.


 

The Body of Evidence

The English King, Richard III, was killed at the Battle of Bosworth on 22nd August 1485.  Contemporary accounts reveal that he was fighting heroically while pressed on all sides by his enemies, the armed forces of the rebel Henry Tudor (later Henry VII).  Famously (and possibly erroneously) depicted by Shakespeare as a murderous, unscrupulous monster, Richard III was the last English king to be killed in battle.  So why am I writing about a long-dead monarch in a forensics blog?  Keep reading to find out! 

 

An archaeological team from the University of Leicester, in association with Leicester City Council and the Richard III Society, has been excavating the site of a mediaeval Franciscan friary in Leicester called Grey Friars. 

On September 12th 2012, while excavating the choir of Grey Friars church, which is believed to be the burial place of Richard III, archaeologists discovered a grave containing human remains.

Could the remains be Richard III?  We shan’t know the answer, or even whether the question can be answered, until early in 2013.  But forensic science is playing a key part in the identification process.

Here is the link to the most recent article on the discovery, which outlines the scientific techniques being employed.  

The Science of the Search for Richard III

 

I imagine that the ‘ancient DNA’ technique being used is Mitochondrial DNA (mtDNA) analysis. Mitochondria (sing. Mitochondrion) are found in the cytoplasm of cells i.e. outside the nucleus.  They are one of the most important ‘organelles’ of a cell, since they are the site of the chemical reactions of respiration, whereby energy is generated for the needs of the cell.  A typical cell contains about a thousand mitochondria.

Old bones, badly decomposed or charred bodies are often poor sources of nuclear DNA, used in standard DNA profiling.  This is because the nuclear DNA becomes degraded, chemically modified or contaminated, and it is not possible to obtain a profile.  Mitochondrial DNA, although not immune to degradation, is better protected within the cell than nuclear DNA.  Its extreme abundance means there is a much greater chance of some of it surviving for longer.  

Human mtDNA is a circular molecule of DNA.  Most of it does not vary between individuals and therefore cannot be used as a forensic identification tool.  However, in a region of the molecule called the ‘D Loop’ or ‘Control Region’, variation does exist in DNA base sequences between unrelated individuals, which is of forensic value.    

I don’t plan to go into the minutiae of the technique here, but I will mention an important point about the inheritance of mtDNA. 

All brothers and sisters in a family will share the same mtDNA as their mother, but not their father.  They will also share the same mtDNA as their mother’s siblings and their grandmother.  This is because an individual inherits their mtDNA only from their mother.

As a consequence, mtDNA analysis cannot provide a unique identification because many individuals can have the same mtDNA base sequences.  Even between unrelated individuals, mtDNA analysis is not as discriminating as standard DNA profiling. The process itself is also not as straightforward as standard DNA profiling.  But it can generate data when standard DNA profiling fails, and this is the technique's undoubted advantage.

I’m very interested to discover that a (male) potential descendant of Richard III’s sister through the female line has been found, so that his mtDNA base sequences can be compared with the base sequences that, hopefully, will be obtained from the mtDNA of the remains.

It would be great if the scientific team are able to find sufficient evidence from their research to suggest that the remains are Richard III.  Follow me on Twitter @forensicswrite to find out.

 



A Question of Expertise

How many Forensic Scientists does it take to change a light bulb?  Answer: Two. One to screw it in and one to check for fingerprints.  Okay, it’s a pretty lame joke, but I’m using it to demonstrate that, in the real world, forensic scientists stick to their own area of expertise.

Each member of the forensic teams of CSI demonstrates proficiency in a wide range of disciplines.  There is seemingly no specialism beyond the scope of their expertise.  The use of such a multi-skilled cast of characters is partly a cost issue, of course.  However, engaging the viewer by re-visiting the characters week by week is a good way of developing loyalty to the show. 

In reality, of course, there is a clear demarcation between examinations carried out at the crime scene and those performed in the forensics laboratory.  Within the laboratory itself, a DNA specialist, for example, would not examine documents or perform toxicological analysis.  Each scientist keeps within their own discipline.

Crime scene investigators ‘read’ and reconstruct the events that took place immediately before, during and after the crime was committed.  They ascertain the type and location of the evidence and collect and package it correctly.  They document and photograph their actions throughout.  They also produce reports on their scene visits, which will form the basis of their expert testimony in court.

In the forensics laboratory, the scientists process the pieces of evidence collected by the scene investigator, whilst documenting all their actions in detail.  They too will produce reports on the results of their analyses, and may be summoned to appear in court as expert witnesses.

So you can see that the two roles are not interchangeable.  However, there is nothing to stop a scene investigator with a suitable science degree from moving into the forensics laboratory and training to become an expert in a single discipline.  They will already have a ‘feel’ for forensics, which can be a big advantage during the early stages of their new career.

Ultimately, it is up to you to decide what sort of forensics expert you want to create.  You could even invent an ‘expert’ who received his certificate of competence to practice from a diploma mill online! 

I’ll finish by wishing all my US readers a Happy Thanksgiving.  I hope you have a wonderful time.



Making an Impression

It is 1979.  A man walks into a bank, covers his face with a balaclava and hands the only cashier on duty a note and a carrier bag.  The note reads:  'I HAVE A GUN.  GIVE ME THE MONEY OR I WILL SHOOT YOU'.  The terrified cashier thrusts some notes into the carrier bag and hands it to the man.  He runs off, just as the cashier manages to activate the alarm..  In his haste to escape, he forgets to ask for the return of his demand note.  Two days later, he answers a knock at the door and discovers two police officers, who have come to arrest him for armed robbery.  He is so surprised that he confesses on the spot.

 

A police officer told me a version of these events many years ago.  The story may be apocryphal, but it serves to illustrate the major impact of a piece of newly operational forensic equipment, not only in solving cases of armed robbery, but also terrorism, murder, fraud and corruption, for example.  The existence of  ESDA (ElectroStatic Detection Apparatus) was not widely known amongst the criminal fraternity in its earliest days, but its use in  a widely reported case of police corruption ensured that its existence eventually became public knowledge.

 

So what is ESDA and what does it do?

 

According to Foster and Freeman, its manufacturers, ESDA is 'the leading technology for detecting indented writing on questioned documents'.  When you write on the top sheet of a pad of paper, the writing will leave indented impressions in the sheets underneath.  In my armed robbery story, indented impressions of the offender's address were found on the demand note.  Just how many sheets will bear impressions depends on the writing implement, the degree of pen pressure and the type of paper.  Writing made with a ballpoint pen with reasonably firm pressure on good quality paper may leave indented impressions on up to six underlying sheets.  On the majority of these underlying sheets, the impressions are not visible on the paper surface.  However, ESDA is such a sensitive technique, that it may be possible to visualise the impressions on all six sheets.

 

The equipment is very easy to operate.  Here is a video of a police officer developing indented impressions in documents from a murder case. 

 

 

 

 

ESDA works by creating an invisible electrostatic image of the indented writing onto the surface of a plastic film.  The impressions are visualised by pouring a mixture of glass beads and charge sensitive toner (like you find in photocopiers) over the surface, until the image is developed.  A permanent record of the image can be made by covering the surface with a sheet of adhesive transparent plastic. Known as an ESDA 'lift', the resultant transparency consists of the plastic film bearing the visualised indented impressions covered by the adhesive plastic.  The lift is trimmed to size and can be used to overlay writing which is suspected of having produced the impressions or simply read for information purposes.  If the impressions are of particularly good quality, they can form the basis of a forensic handwriting comparison with a suspect's writing.

 

A variety of information can be obtained from indented impressions.  If a page has been torn out of a diary, ESDA may be able to detect what was removed by examining the pages on either side.  In a murder case, where the victim knew her attacker, the victim had made a note in her diary that she would be meeting her attacker on this particular day.  Whilst checking that there was nothing to connect him with the crime, the murderer discovered the victim's diary.  He tore out the offending page and threw it away.  An ESDA examination of the pertinent pages of the victim's diary revealed the attacker's name.

 

A man committed suicide and left a bitter note for his wife.  She has destroyed the note because she feels she drove her husband to take his own life and cannot face his family.  Eventually, she tells the police that there was a note and it had been written on the pad by the telephone.  An ESDA examination of the top sheet of the pad would show exactly why her husband committed suicide and why she felt so guilty.

 

A suspect in a case of money laundering passed four handwritten receipts to the police, which, he stated, accounted for four large payments made into his business bank account.  The receipts covered a four month period between June and September 2007 and were dated at monthly intervals.  The police suspected that the receipts were false and had been created purely to legitimise the transactions.  Were the dates on the receipts genuine?

 

By using ESDA, it was discovered that there were indented impressions of the writing from the receipt dated in September 2007 on the receipts dated in August, July and June 2007.  There were also impressions of the August receipt on the July and June receipts and impressions of the July receipt on the June receipt.  This is clearly impossible if the receipts are dated correctly.  Undoubtedly, all the receipts had been written at one sitting and their dates were not genuine.

 

I'm sure you could think of many more examples where ESDA would be invaluable in helping to solve crimes.

 

A big bonus of the ESDA technique is that the document containing the impressions is not damaged in any way,  Furthermore, provided that the document has not been treated with fingerprint reagents, the technique still works after many years, and could, therefore, be of value in cold cases.

 

So when your characters decide to send a handwritten anonymous letter or plan an armed robbery on paper, they should take care what they leave behind!

Forensic Meteorology - more than Blue Sky Thinking

It was a dark and stormy night.  Okay, so no crime writer worthy of the name would ever begin a novel with such a tired sentence.  But in a murder investigation, detectives may need to establish that it was stormy on a particular night.  They may need to know when the storm started and what impact it had at ground level, for example. 

 

The investigating officers could consult weather reports and get an overview of the conditions in the area.  However, only a Forensic Meteorologist will be able to supply the precise details of the weather at the specific time and location pertinent to the investigation.

 

Forensic Meteorologists reconstruct weather conditions that occurred at a particular time and location, rather than predicting what the weather will be like.  Using a variety of archived data sources, including radar, satellite imagery, local weather station observations and National Weather Service bulletins, a Forensic Meteorologist will analyse the data and recreate a timeline of weather events for a certain location on the desired day.

 

Most of the work of a Forensic Meteorologist involves civil cases.  Did the person who broke their leg after a fall in the street, really slip on some ice or had the ice melted some hours before?  Did lightning really spark a fire which caused extensive damage to a house or did somebody fall asleep with a burning cigarette in their hand? 

 

Insurance companies are good clients of Forensic Meteorologists.  The roofing and engineering industries also have good reason to engage Forensic Meteorologists.  If a roof is allegedly damaged by hail, for example, a Forensic Meteorologist can provide a scientifically accurate report that will verify the presence or absence of hail at the address in question.

 

In criminal cases, a Forensic Meteorologist may be able to break a murderer's alibi.  In 2002, Michael Mosely was accused of bludgeoning two people to death in Troy, New York State.  When he was arrested, Mosely had a cut on his hand.  He claimed the cut was not suffered during the killings but happened while he was snowboarding with his son.  The DA's office in Rensselaer County, NY called in Howard Altschule, an experienced Forensic Meteorologist.

 

Mr Altschule testified that at the time Mosely said he was snowboarding, it was actually raining.  Using radar maps, Mr Altschule was able to show precisely where and when the rain was falling.  Although the rain was light, it was significant enough to melt any snow.  Mosely's alibi was destroyed.  The jury found him guilty of both murders.

 

In another criminal case, Howard Altschule's evidence was crucial in assisting the prosecution.  In 2009, Omar Long stood trial for the manslaughter of his daughter, Arianna, aged 23 months.  Long left Arianna in his car, so he could take a nap.  While he slept, Arianna died.  The cause of death was hyperthermia - extreme heat exhaustion; the post-mortem also revealed that she had second degree burns on her body.

 

Watch an interview with Howard Altschule, where he explains what happened to the temperature inside the car.

 

 

 

Long was found guilty of manslaughter by culpable negligence and sentenced to 12 years imprisonment.  He appealed unsuccessfully against his sentence earlier this year.

 

The field of forensic meteorology is growing fast, although its use in criminal cases is probably under-exploited at present.  I'm sure forensic meteorology could form the basis of some inventive plot lines.  Do you agree?