Detecting Deposition Sites

• Aerial photography

  • Location of possible site

  • Different image depending on time of year/crops etc.

  
• Methods of detection

  •The process of body deposition and the decomposition changes that it undergoes give opportunities for detection of the body.

  •Changes to soil profile

  •Changes to vegetation

  
• Soil Profile

  • Plan View: Grave Surface

  Secondary Depression Primary Depression - entire grave surface

  • Grave Profile

  
• Vegetation

  •On surface decomposition can have a negative effect on plants due to smothering and leachate-liquids that leak from body

  •Soil disturbance and trampling of vegetation can lead to different species growth (e.g. poppies on battle grounds)

  •It is important to look for pioneer plants and new, young plants that both indicate recent disturbance.

  
• High nitrogen and ammonia content in burials cause death of some plants which are replaced by those that like a soil with a high pH such as nettles

  Rich nutrients from decomposing body and increased aeration of the soil during excavation may encourage rapid plant growth

  A body wrapped in plastic may reduce nutrient content of soil resulting in retarded plant growth in the area of the grave

  Plants may also be damaged by disturbance caused during the process of digging the grave including trampling and covering by the upcast or throw remnants on the ground surface

  
• Detection of remains through odour

  Decomposition odours can be useful in detection of human remains:

  •Cadaver dogs

  •Field portable instruments (decompositional odour analysis (DOA) database

  Lot of work done by Vass.

  In both these situations there is a need to vent the area of possible burial
• Decomposition fluids and gases

  • Shown to be very complicated - up to 478 different compounds during the decomposition time frame

  •Due to the many taphonomic influences it is not possible to say which compound present at which time

  •Volatile Organic Compounds

  • Scent dogs can be used to detect volatile organic compounds – putrescine and cadaverine

  
• Identification of primary deposition site

  •Can use chemicals of decomposition to identify that a body has been in situ for a period of time

  •Relies on products of decomposition leaching out into surrounding
• Thermal imaging

  •Shows up heat sources

  •Good for missing

  •Can be used recently deceased-even with shallow burial

  •May be some argument for using during active decomposition for surface deposition

  
• GPR-Ground penetrating radar

  •Most commonly used of all geophysics search methods

  •Transmission of electromagnetic wave energy. Travels faster through less dense (i.e. disturbed soil)

  •Indicates anomalies which have to be interpreted and explored

  •Can be problems therefore in urban areas-tree roots etc.

  •Good for penetrating concrete or paved layers •Problems with clay soils

  
• Resistivity

  •Detects electrical current in subsurface soils

  •Measures organic content soils, moisture etc.

  •Historic and contemporary debris can cause problems •Surface disturbances

  •Dry soil and frozen ground problematic

  
• Magnetometry

  •Measurement of earth’s magnetic field-versus other magnetic fields

  •Looking for areas where magnetism is higher or lower than expected

  •More useful in less disturbed soils

  •Problematic in urban areas - e.g power lines

  •Has been used in search for burnt remains such as Sturdy Colls investigations of the Holocaust (on reading list)
• Water detection: Ground Penetrating Radar

  
• Scent Dogs

  Many decomposition products are water soluble