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?

 

  

 

Bloodstain Removal - a Killer's Dilemma

‘Did you ever notice how they have commercials on TV with detergents that can get out bloodstains?  If you have blood all over your shirt, I don’t think laundry is your biggest problem’.  Jerry Seinfeld  

It is virtually impossible to remove bloodstains from a crime scene.  The assailant who has killed his victim in a kitchen or bathroom with easy to clean surfaces may feel confident that no trace of his crime remains.  However, tiny specks of blood can remain in the room and, crucially, may still be there many years after the killing. 

A particularly difficult cleaning problem confronts the assailant who has committed his murder surrounded by absorbent surfaces like carpets, curtains and bedding.  Cold water is probably the most effective way to remove bloodstains – to the naked eye, at least.  Hot water just fixes the stain and the use of chlorine-based bleach turns the bloodstain a pale green-brown.

Blood visualisation chemicals, such as the highly sensitive Bluestar®  Forensic reagent, can reveal the presence of bloodstains that have been wiped away, washed out, or are invisible to the naked eye.  The haemoglobin (an oxygen-carrying protein) in the blood reacts with the chemicals in the reagent to produce the glow-in-the-dark effect much beloved of television producers.  This process is known as chemiluminescence. 

But what if a substance existed that would remove haemoglobin? Bluestar® Forensic reagent cannot work without the presence of haemoglobin. 

I mentioned that chlorine–based bleach is ineffective at bloodstain removal.  However, there is another type of bleach found in some household cleaning products – including washing powder – that contain oxygen bleach.  Scientists at the University of Valencia in Spain have discovered that oxygen bleach removes haemoglobin.

Their tests showed that washing powders containing oxygen bleach will not only make bloodstains fade but they will also make them unreactive to blood visualisation chemicals, owing to the removal of the haemoglobin from the stain.

The killer’s dilemma now becomes the forensic scientist’s dilemma. Even if a stain is still visible, because it is unreactive, it will not automatically be tested for DNA, since it has not been verified as being of human origin.  This means that useful evidence may, potentially, be lost.

But, it takes only a drop of the victim’s blood on a suspect’s clothes to confirm that the suspect was at the scene at the time of the attack.  Blood embedded in the seams is very resistant to washing and can be easily missed in the assailant’s clean-up operation.

Cold cases heat up through new approach to identifying remains

Cold cases heat up through new approach to identifying remains

I found this article in Science Daily that I thought I would share with you.  It describes how a multidisciplinary approach allowed the legal identification of a person whose remains had been discovered 41 years previously.  I thought it was a very interesting article; I hope you like it too.

 

All my blog posts are designed to help you with forensics techniques and maybe provide you with a bit of plot inspiration at the same time.  My 'Scenes of Crime' newsletter is also designed for the same purpose. 

However, owing to a few production issues (aka my ineptitude!), future issues of 'Scenes of Crime' will be delivered as opt-in e-mails.  You will be able to sign-up to receive them in the next 2 or 3 weeks, and I'll do my very best to stick to a monthly schedule. 

Don't forget to send me your questions for 'Forensic Fix-it'.

DNA Debacle: the sequel

I’ve been busy with urgent casework these last few days, so my apologies for posting only once this week.

One of the news items that I highlighted in the June/July edition of Scenes of Crime concerned the case of Adam Scott, who was charged with rape based on DNA evidence, despite maintaining that he had never visited the city where the rape occurred.

LGC Forensics, the largest private forensics company in the UK, had recently introduced a robotic DNA extraction system at the time the rape case sample was processed.  An investigation revealed that a technician had incorrectly re-used some plastic trays, resulting in a contaminated profile.

Even before the contamination came to light, the investigating officer had expressed concerns about the DNA result.  An analysis of Adam Scott’s mobile phone records revealed that he was 300 miles away when the rape took place.  However, LGC Forensics initially refused to consider the possibility of contamination.

Charges against Mr Scott were eventually dropped, but not before he had spent 5 months in prison.

An independent report from the Forensic Regulator, whose task is to monitor the quality of procedures used in forensic science, found that Adam Scott was an ‘innocent victim of avoidable contamination’.  The report stated that LGC Forensics’ DNA rape sample procedures were ‘not adequate’, and disclosed poor record keeping by technicians and failure to follow procedures for the disposal of used plastic trays.

LGC Forensics was also criticised for not responding more fully to the discovery that the plastic trays were being re-used.  However, the Forensic Regulator conceded that the company had now taken corrective action to address the shortcomings in its contamination avoidance and checking procedures.  No other instances of contamination had occurred.  

This incident adds more fuel to the argument that the private sector is incapable of absorbing the caseload of the now defunct Forensic Science Service of England and Wales.  I don’t happen to share this view.  The private sector knows how to operate a forensic science business; the Forensic Science Service was never equipped to operate as a business.  Nevertheless, this was a regrettable and inexcusable incident of ‘human error’ and Adam Scott may well be suing for compensation.

Listen to Adam Scott's grandparents talking about the case.