Forensic Science: Understanding Decomposing Bodies

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    • 00:07

      [Foreign Science: Understanding Decomposing Bodies]

    • 00:11

      DR. ANNA WILLIAMS: My name is Dr. Anna Williams.[Dr. Anna Williams, Principle Enterprise Fellow,University of Huddersfield] I'm a Forensic Anthropologistand a Principle Enterprise Fellow at the Universityof Huddersfield.I'm involved in teaching on the undergraduate forensic coursesand the Master's in forensic anthropology.And I also do research with Ph.D. and Master students.As a forensic anthropologist, one of my main interests

    • 00:33

      DR. ANNA WILLIAMS [continued]: is human decomposition, i.e. the processesthat happen to us as we decompose after we die.One of the most important things to find out,as part of a criminal investigation,is how long the body has been there,how long the person has been dead,or the post-mortem interval.Taphonomy is the study of decay and decomposition processesof animals and humans in a variety

    • 00:56

      DR. ANNA WILLIAMS [continued]: of different environments.In a forensic context, that sort of researchis useful and interesting to the forensic scientistsbecause it will help us determinethe post-mortem interval, how long the body has been there.But also it will help us work out who the person is.A pathologist tends to look at the soft tissue

    • 01:17

      DR. ANNA WILLIAMS [continued]: of the body and the organs.But an anthropologist specializes in the hard tissuesof the body, and tends to look at the bones and the teethto get their information.An anthropologist will be called in to a scene of a crime.If the body is in a compromised state, i.e.

    • 01:39

      DR. ANNA WILLIAMS [continued]: it's badly decomposed, or it's been submergedin water or something like that has happenedto it, which means that it is not very readily identifiable.Forensic anthropologists need to understandhow human bodies decompose.Unfortunately, in the UK, at the moment,it's not possible to do this sort of research

    • 01:60

      DR. ANNA WILLIAMS [continued]: using donated human cadavers.So lots of academics and researchers rely on using pigsas analogues for human bodies.OK.So this is one of our pig samples.It's been here for 140 days, roughly.They are reasonably close to humans in their physiology,

    • 02:25

      DR. ANNA WILLIAMS [continued]: in their muscle-to-fat ratio, their organs are quite similar,their skin is quite similar, their bones are quite similar.And they're omnivores.They have similar gut bacteria to us,which is very important for decomposition.This is how we would take the gas sample.This is an SPME fiber.What we'd do is put it inside the specially created hole

    • 02:49

      DR. ANNA WILLIAMS [continued]: in the box.We would leave it here for roughly 40 minutesto collect all the volatile organic compounds that itcould.There are some things that we can never study accurately,using pigs, for example, the effect of dieton decomposition, the effect of smoking,the effect of human diseases, such as diabetes, or cancer.

    • 03:14

      DR. ANNA WILLIAMS [continued]: Those could all have important effectson the rate of decomposition and the types of decompositionprocesses.OK.So this is the SPME fiber that has collected the gases.And we would take it down to the GC-MS machineto analyze what those gases were.And now that we've done that, we can open the boxand have a look at the cadaver.

    • 03:36

      DR. ANNA WILLIAMS [continued]: The way that we study pig decomposition iswe use these specialized outdoor laboratoriescalled Taphonomy facilities.And they are usually large areas of landthat have different types of habitatand different types of vegetation on them.And we put pigs out in different situations

    • 03:57

      DR. ANNA WILLIAMS [continued]: and we watch how the various conditionseffect their decomposition.This is a small piglet.It's died of natural causes.It's been here for about 140 days.And as you can see, it's very far advancedin it's decomposition.

    • 04:17

      DR. ANNA WILLIAMS [continued]: It's almost skeletinized.You can see some of bones visible.But it still has it's layer of skin and it's layer of fur.And you can also see around it all the remainsof the insects that have colonizedand couldn't get out of the box.OK.So we'll box it back up and have a look at another one.

    • 04:38

      DR. ANNA WILLIAMS [continued]: In America, and now recently in Australia,they have large Taphonomy facilities for using humans,donated human cadavers through donation programs.And there, they will put the bodies outin all sorts of different environments, sitting in cars,

    • 05:01

      DR. ANNA WILLIAMS [continued]: wrapped up in duvets, hanging from trees, buried,in water, all sorts of things, to find outhow decomposition happens in those varied environments.OK.So this one is quite different.It's only been here about, roughly, 80 days.Yet, it's completely skeletonized.

    • 05:23

      DR. ANNA WILLIAMS [continued]: And all the skin and fur has decomposed.So you can see a lot of the individual bones.You can see it's skull and it has broken apart.Because it was a young pig, it's skull wasn't fully fused.We don't fully understand, yet, howhuman bodies, different human bodies,

    • 05:45

      DR. ANNA WILLIAMS [continued]: decompose in our climate with our specific floraand fauna, our vegetation, our insects, our scavengers.So having a human Taphonomy facility in the UKwould help us finally get that baseline thatwould form the springboard for lots of other researchto understand exactly how human decomposition happens.

    • 06:06

      DR. ANNA WILLIAMS [continued]: So here we are at the GC-MS machine.We put our CPME fiber that has absorbed all the chemicalsfrom the pig in the box.We put it in here.And then it provides us with a spectra of peaks.And we can compare those peaks to a libraryand work out exactly which chemicals were on this fiber.

    • 06:28

      DR. ANNA WILLIAMS [continued]: So if a body comes to the lab and it's very badly decomposed,then one of the first things we'll dois assess the state of decomposition.We're trying to work out how decomposedit is, how far along in the processit is to skeletonization, in orderto work out the sort of conditions that it's been in,

    • 06:50

      DR. ANNA WILLIAMS [continued]: if we don't necessarily know from the case report.And to work out how long it's been dead,we'll give each part of the body a different scoreof how decomposed it is.Things we're looking for are things like skin discoloration,skin slippage and blistering.

    • 07:11

      DR. ANNA WILLIAMS [continued]: We'll be looking for evidence of bacterial activityin the intestines, insect colonization, that'swhen an entomologist would come in and join the investigation.If it's more skeletonized, then wewould try to clean up the skeleton.Look for characteristics on the skeletonthat help anthropologists work out the sex of the individual,

    • 07:36

      DR. ANNA WILLIAMS [continued]: how old it was when it died, maybe something about it'sethnic ancestry, and we might be able to work outhow tall it is.And we would also look for signs of any pathological conditionsthat had effected the body during it's life,

    • 07:57

      DR. ANNA WILLIAMS [continued]: and any signs of trauma that might give usan indication of how it died.There are all sorts of things that you canfind from skeletal evidence.For example, if you look at the trauma,you might be able to reconstruct the sequence of eventsleading to their death.So you might be able to say that they've been hit on the head

    • 08:17

      DR. ANNA WILLIAMS [continued]: twice with a hammer, or they wereshot at point blank range, all of whichwill help you work out who the culprit was.One of the jobs of a forensic pathologistis to determine cause of death.But an anthropologists job is to determine manner of death.

    • 08:40

      DR. ANNA WILLIAMS [continued]: And that is quite an interesting distinction.A cause of death might be somethingthat effects the brain, or the heart, or the lungs,to stop your heart beating, or to stop your breathing,or to stop your brain function.So for example, a cause of death might be a subdural hemorrhage,where your brain is bleeding and cannot function anymore.

    • 09:01

      DR. ANNA WILLIAMS [continued]: But the anthropologist is interested in howthat subdural hemorrhage came into existence.So for example, somebody might have been hit over the headwith a baseball bat, that will be the manner of death.We look for clues around the body thatmight give us an indication of how long the person hasbeing there.One example, one of the cases that I've done,

    • 09:23

      DR. ANNA WILLIAMS [continued]: is where I was asked to examine a skull and a few arm bones.And it was thought, from the context of howit had been found, that it was an archaeological skull,it had come from a cemetery or an archaeological siteclose to where it had been found.

    • 09:44

      DR. ANNA WILLIAMS [continued]: But when I carefully cleaned up the skulland cleaned the teeth, I found that it hada filling, an amalgam filling.And so, therefore, it must have beenmore recent than had been originally thought.And therefore, it was more likely to bea forensic case and in the forensic timescale of interest.

Forensic Science: Understanding Decomposing Bodies

View Segments Segment :


Dr. Anna Williams discusses forensic anthropology and using decomposition to determine cause and time of death. Forensic anthropologists study taphonomy, the study of decay and decomposition, and are interested in bones and teeth, not soft tissue. In the UK, studies cannot use donated human cadavers, so they use pigs because of their physiological similarity to humans.

SAGE Video In Practice
Forensic Science: Understanding Decomposing Bodies

Dr. Anna Williams discusses forensic anthropology and using decomposition to determine cause and time of death. Forensic anthropologists study taphonomy, the study of decay and decomposition, and are interested in bones and teeth, not soft tissue. In the UK, studies cannot use donated human cadavers, so they use pigs because of their physiological similarity to humans.

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