Mapping techniques

Question 1

What are the 4 stages of forensic recovery?

Answer 1

1. Location – searching for the remains above or below ground.
2. Mapping – grid the site to ensure detailed documentation of recovery.
3. Excavation (where appropriate)
4. Collection – proper packing of remains for further laboratory-based analysis.

Question 2

What are key variables in forensic context?

Answer 2

• Depth of time
• Intent of placement

Question 3

What are indicators of forensic circumstances to assess?

Answer 3

• Location of remains
• Position & orientation of body
• Preservation state
• Associated artefacts & evidence

Question 4

What are the types of search areas?

Answer 4

• Open
• Obstructed
• Submerged

Question 5

What are the different search methods?

Answer 5

• Aerial reconnaissance
• Walking grids
• Remote sensing

Question 6

What do all search techniques be in accordance with?

Answer 6

“All techniques used must comply with relevant legislation and be demonstrably fit for defined purpose(s).”

Question 7

What are questions to ask when locating remains?

Answer 7

• When did the event occur?
• Height and weight of individual?
• How deep was the body buried?
• Was the body wrapped in anything?
• Was the body clothed?
• What were the local conditions in the area?
• Was anything placed over the grave to conceal its location?
• Were there any unique landmarks?
• Has the landscape changed since the burial?

Question 8

What search method is best for small teams or hillside areas?

Answer 8

Spiral

Question 9

Spiral search method

Answer 9

• Works best for small teams or hillside locations
• Ensures no inadvertent trampling of evidence
• Reverse pattern used for searching for scattered remains

Question 10

Strip/line search method

Answer 10

• Most common
• 100% coverage if properly executed
• Each line directed by team leader in middle of line
• Forensic specialist walk behind the line and inspect marked items of interest

Question 11

Grid search method

Answer 11

• More time-consuming variation of strip/ line search
• Advantage: multi-directional and multi-angled search
• Helps account for light-mediated
  revealing/obscuring of evidence.

Question 12

Quadrant/zone search method

Answer 12

• For detailed searches of small areas
• Often implemented after remains have
  been found

Question 13

What are the different types of search method?

Answer 13

• Spiral
• Strip/line
• Grid
• Quadrant/zone

Question 14

What are indicators of surface deposits?

Answer 14

• Skeletal remains and soft tissue
• Clothing, personal objects and weapons
• Decomposition odour and staining
• Insect activity
• Loose trash or brush heaps
• Animal activity and scavenging
• Materials used for wrapping body

Question 15

What are indicators of buried remains?

Answer 15

• Mounding of dirt
• Primary burial depression filled with leaf litter
• Ground cover that varies from surrounding plant growth due to disturbance of topsoil
• A burrow possibly from a scavenging animal
• Mixed soil

Question 16

What are indicators used to locate buried bodies?

Answer 16

• Skeletal remains and soft tissue brought to the surface
• Clothing or personal effects
• Insect activity
• Evidence of animal digging and scavenging
• Abandoned tools or weapons
• Soil or vegetation disturbance (Growth, lack of growth, colour change)
• Depressions, soil disturbances or unnatural mounding of soil
• Soil colouration changes from the mixing of soil layers
• Decomposition odour
• Decreased soil compaction
• Areas where bushes or tree limbs have been moved to conceal something

Question 17

What are cadaver dogs?

Answer 17

• Specially-trained dogs to detect scene of human decomposition (whole bodies, body parts, body fluids).
• Dog tracks scent cone

Question 18

How do scent cones work?

Primary, wind, water

Answer 18

• Primary scent pools form above and around decomposing remains
• Variable winds can cause uneven dispersal of scent molecules or multiple scent cones around the remains
• Water may move the scent away from the source in response to currents, gravity, surface or underground waterways, erosion or drainage patterns

Question 19

Where do scent voids form?

Answer 19

Scent voids near the remains can form in areas where water flow interrupts the absorption of decomposition fluids into the soil or in cases where the body is elevated in relation to the ground surface.

Question 20

Why do scent cones form?

Answer 20

Scent cones form as scent molecules are dispersed away from the source by airflow or thermal uplifting.

Question 21

What may scent barriers form?

Answer 21

Scent barriers may form remote secondary scent pools and scent cones

Question 22

What are the three types of probes?

Answer 22

• T-bar
• Penetrometer
• Soil-coring

Question 23

What does a t-bar measure?

Answer 23

Qualitative changes in soil compactness

Question 24

What does the penetrometer measure?

Answer 24

Quantitative changes in soil compactness

Question 25

What does the soil corer check?

Answer 25

Check for mixing of soil horizons

Question 26

What's the problem with probes?

Answer 26

- Not useful over larger areas - Can be destructive

Question 27

What should you do when mapping a recovery site?

Answer 27

- Set up a datum on a permanent structure and note the GPS coordinates of the point - Set up a grid over the area of the remains 3-4 meters square with four wooden posts connected with strings - Tape measure from the height of string to document the location of each artefact of biological item. - Detailed photography

Question 28

What are the non-destructive parts of excavation & recovery?

Answer 28

- Examine & record the recovery area - Establish spatial controls & record secondary surface deposits

Question 29

What are the destructive parts of the excavation and recovery methods?

Answer 29

- Expose & record primary surface deposit - Remove loose debris one grid at a time - Remove/trim surface vegetation to expose remains for recording & mapping. - Record and map all exposed evidence. - Remove surface remains - Examine soil layer beneath surface deposits - Remove any buried remains/evidence.

Question 30

What are the different methods of locating remains?

Answer 30

- Conductivity meter - Resistivity meter - Magnetometer/metal detector - LiDAR - NIR - Ground-penetrating radar - Side-scan sonar

Question 31

What does LiDAR stand for?

Answer 31

Light Detection And Ranging

Question 32

What are the two types of LiDAR?

Answer 32

- Topographic surveying (land) - Bathymetric surveying (aquatic)

Question 33

What are the factors which affect resultant elevation?

Answer 33

- Burial context (number of individuals, size of grave, completeness of backfilling) - Time elapsed since burial (soil settling, decomposition, organic debris accumulation)

Question 34

What are the two types of elevation changes?

Answer 34

- Change to the full extent of the grave/disturbance footprint - Change directly atop interred bodies

Question 35

What can a side-scan sonar be used to locate?

Answer 35

Submerged remains

Question 36

What are the methods for mapping recovery sites?

Answer 36

- Total station - Photogrammetry

Question 37

How does a total station work? | Azimuth

Answer 37

❑ It uses a combination of stadia rods (known height, marked with known measurements) and transit (precision telescope for recording measurements on the stadia). ❑ Record distance, azimuth (angle) & change in elevation for accurate mapping of items relative to fixed point.

Question 38

How could you excavate and record a burial feature for buried remains? | Corner

Answer 38

- Working from the corner & across the grid, remove soil in 5 cm layers using a hand trowel & brushes. - Screen all soil removed.