Evidence Collection

Evidence CollectionEvidence Collection

The collection of physical evidence is an integral part of a properly conducted fire investigation.

Overview of Evidence Documentation and Collection

Focus on Accelerant Collection whether liquid or liquid absorbed by solid material or solid samples (containers)

Review of Legal Considerations

The collection of physical evidence is an integral part of a properly conducted fire investigation.

Overview of Evidence Documentation and Collection

Focus on Accelerant Collection whether liquid or liquid absorbed by solid material or solid samples (containers)

Review of Legal Considerations


Evidence includes evidentiary and interpretive use of fire patterns in the identification of a potential ignition source. These will include thermal effects such as charring, oxidation, melting, colour changes, consumption of combustibles

This lecture will focus specifically on the documenting and collection of evidence for accelerant testing

For specifics on the collecting of other evidence during a fire investigation – follow guidance from OPS Arson Investigators

Currently there is no provisions by City of Ottawa or OFS for the retention of evidence.

Evidence includes evidentiary and interpretive use of fire patterns in the identification of a potential ignition source. These will include thermal effects such as charring, oxidation, melting, colour changes, consumption of combustibles

This lecture will focus specifically on the documenting and collection of evidence for accelerant testing

For specifics on the collecting of other evidence during a fire investigation – follow guidance from OPS Arson Investigators

Currently there is no provisions by City of Ottawa or OFS for the retention of evidence.


Evidence ContainersOFS Investigators are supplied with glass containers (Mason

jars, 1 litre) for evidence collection

Mason jars are sterilized and documented prior to being in service. Washed in dishwasher with heated dry and no detergents used. Document process when done in notes, re-seal box using Ident tape and sign, date.

OPS Evidence Bags provided in 2 sizes. Bags are number and when collecting evidence reference # in notes.

If stock is low on bags and ident tape – notify OPS Arson Sgt.

Evidence ContainersOFS Investigators are supplied with glass containers (Mason

jars, 1 litre) for evidence collection

Mason jars are sterilized and documented prior to being in service. Washed in dishwasher with heated dry and no detergents used. Document process when done in notes, re-seal box using Ident tape and sign, date.

OPS Evidence Bags provided in 2 sizes. Bags are number and when collecting evidence reference # in notes.

If stock is low on bags and ident tape – notify OPS Arson Sgt.


Possible Indicators of an Accelerated Fire1. Witness Observations

2. A low pressure wave (‘whomp’ sound)

3. An explosion

4. Flash burn injuries to the hands, face, legs or hair of a suspect or witness

5. Unnatural fire spread (downward, unusually fast)

6. “Rolling” flames

7. Bright yellow/orange flames accompanied by black smoke

8. Sudden appearance of flames in an entire room followed by heavy, pushing black smoke

9. Flames seen burning directly from the floor

Possible Indicators of an Accelerated Fire1. Witness Observations

2. A low pressure wave (‘whomp’ sound)

3. An explosion

4. Flash burn injuries to the hands, face, legs or hair of a suspect or witness

5. Unnatural fire spread (downward, unusually fast)

6. “Rolling” flames

7. Bright yellow/orange flames accompanied by black smoke

8. Sudden appearance of flames in an entire room followed by heavy, pushing black smoke

9. Flames seen burning directly from the floor


10. Intense, localized scalding or rusting/warping, especially to the undersides and lower portions of metal appliances and metal objects within suspected liquid burn pattern area

11. Structural damage inconsistent with fire loading

12. Intermixed light, moderate and intense floor burn patterns in puddle or trailer shapes

13. Localized ‘gapping’ of wood or vinyl floor seams with the pour burn pattern

14. Rainbow coloured sheen on the surface of suppression water

15. Even height of smoke and burn patterns in the room of origin

16. Accelerant containers in or near the scene

10. Intense, localized scalding or rusting/warping, especially to the undersides and lower portions of metal appliances and metal objects within suspected liquid burn pattern area

11. Structural damage inconsistent with fire loading

12. Intermixed light, moderate and intense floor burn patterns in puddle or trailer shapes

13. Localized ‘gapping’ of wood or vinyl floor seams with the pour burn pattern

14. Rainbow coloured sheen on the surface of suppression water

15. Even height of smoke and burn patterns in the room of origin

16. Accelerant containers in or near the scene


17. Increased burn damage pattern at the bottom of furniture legs, boxes etc. on the floor of the pour pattern area

18. Burn patterns beneath doors, thresholds or floor mouldings19. Rundown burn patterns on floor joists beneath loose floor

boards, board seams or edge mouldings20. Localized staining on the underside of carpet padding21. Pool-shaped, intermixed mottled black and brown staining

on a concrete floor, together with a tendency for the area to repel water – stained area also may contain odour of pour

22. Fire damage with no identifiable point of origin23. Wall burn patterns running from the floor seam up or

appearing in corners24. Burned out flooring beneath heavy appliances or furniture

that would ordinarily be expected to ‘protect’ the floor

17. Increased burn damage pattern at the bottom of furniture legs, boxes etc. on the floor of the pour pattern area

18. Burn patterns beneath doors, thresholds or floor mouldings19. Rundown burn patterns on floor joists beneath loose floor

boards, board seams or edge mouldings20. Localized staining on the underside of carpet padding21. Pool-shaped, intermixed mottled black and brown staining

on a concrete floor, together with a tendency for the area to repel water – stained area also may contain odour of pour

22. Fire damage with no identifiable point of origin23. Wall burn patterns running from the floor seam up or

appearing in corners24. Burned out flooring beneath heavy appliances or furniture

that would ordinarily be expected to ‘protect’ the floor


25. Ghost marks between the seams of vinyl floor tiles in the pour area where the ignitable liquid seeped, dissolved and scorched tile adhesive, resulting in a checkerboard pattern on the sub-floor

26. Sharp line of char demarcation in a cross-section of wood stud, or a sharp line of calcination (colour change) in plaster or drywall, indicating rapid heat build up

27. Window glass that has melted down like ribbon candy and has a clean interior face (little or no soot) on the fire side

28. Spring annealing – sometimes a result of a pour29. Inverted cone burn/scald patterns on vertical surfaces within

the pour pattern area.30. Localized clean burn areas on wall, appliance or non-

combustible horizontal or vertical surface above a floor pattern

25. Ghost marks between the seams of vinyl floor tiles in the pour area where the ignitable liquid seeped, dissolved and scorched tile adhesive, resulting in a checkerboard pattern on the sub-floor

26. Sharp line of char demarcation in a cross-section of wood stud, or a sharp line of calcination (colour change) in plaster or drywall, indicating rapid heat build up

27. Window glass that has melted down like ribbon candy and has a clean interior face (little or no soot) on the fire side

28. Spring annealing – sometimes a result of a pour29. Inverted cone burn/scald patterns on vertical surfaces within

the pour pattern area.30. Localized clean burn areas on wall, appliance or non-

combustible horizontal or vertical surface above a floor pattern


Whether alone or with Fiesta & Ian – you’ve found a possible accelerated arson scene

Photograph the scene prior to evidence collection

As pieces of potential evidence are recovered, photograph each in place and fix its location either in notes or a sketch

Use the photo numbers when documenting evidence

Whether alone or with Fiesta & Ian – you’ve found a possible accelerated arson scene

Photograph the scene prior to evidence collection

As pieces of potential evidence are recovered, photograph each in place and fix its location either in notes or a sketch

Use the photo numbers when documenting evidence


Evidence Collection AreasMost desirable collection areas are:a. Lowest areas and insulated areas within the

patternb. Samples taken from porous plastic or manmade

fibresc. Cloth, paper, cardboard in direct contact with the

patternd. Inside seams, tears, crackse. The edges of burn patternsf. Floor drains, bases of load bearing columns or

walls

Evidence Collection AreasMost desirable collection areas are:a. Lowest areas and insulated areas within the

patternb. Samples taken from porous plastic or manmade

fibresc. Cloth, paper, cardboard in direct contact with the

patternd. Inside seams, tears, crackse. The edges of burn patternsf. Floor drains, bases of load bearing columns or

walls


Evidence Collection AreasLeast desirable collection areas:a. Deeply charred woodb. Gray ashc. Edge of hole burned through a floord. Samples from absolutely non-porous

surfacese. The center of any burn patternsf. In general, areas exposed to the greatest

heat or hose streams

Evidence Collection AreasLeast desirable collection areas:a. Deeply charred woodb. Gray ashc. Edge of hole burned through a floord. Samples from absolutely non-porous

surfacese. The center of any burn patternsf. In general, areas exposed to the greatest

heat or hose streams


Preventing Cross-contamination

Tools: tools are to be cleaned after every scene or when used for evidence collection. Tools should be rinsed clean with a strong stream of water (scrubbing with paper towel) – and documented

Clothing (PPE): Boots should be cleaned after every use – stream of water. Never wear your fire gloves when collecting evidence. Use nitrile or latex gloves.

Preventing Cross-contamination

Tools: tools are to be cleaned after every scene or when used for evidence collection. Tools should be rinsed clean with a strong stream of water (scrubbing with paper towel) – and documented

Clothing (PPE): Boots should be cleaned after every use – stream of water. Never wear your fire gloves when collecting evidence. Use nitrile or latex gloves.


Ignitable liquid Accelerant SamplesOnly a few ounces of liquid is required to be takenSterile gauze bandage may be used for skimming suspected

residue sheen of the surface of suppression water. Submit a comparison sample

If suspected ignitable liquid container found in scene, you can take a small sample of the suspected liquid outside of the fire scene to perform a test ignition and the burning of the suspected liquid. Document actions

Once filled – seal the container lid with Ident tape and label the container with: Incident Number, Exhibit Number, Time and Date of seizure and who seized it. If required – a notation of contents is recommended.

Ignitable liquid Accelerant SamplesOnly a few ounces of liquid is required to be takenSterile gauze bandage may be used for skimming suspected

residue sheen of the surface of suppression water. Submit a comparison sample

If suspected ignitable liquid container found in scene, you can take a small sample of the suspected liquid outside of the fire scene to perform a test ignition and the burning of the suspected liquid. Document actions



Use of sterile gauze to collect floor sampleUse of sterile gauze to collect floor sample


Container & Contents SeizedContainer & Contents Seized


Solid Fire Debris SamplesEvidence container should be filled to two-thirds volume with

debris sample, leaving top one-third volume as empty ‘headspace’

This ‘headspace’ is the area that the labs take their samples from for testing.

When filling the container do not pack down the sample


Document in notes

Solid Fire Debris SamplesEvidence container should be filled to two-thirds volume with

debris sample, leaving top one-third volume as empty ‘headspace’

This ‘headspace’ is the area that the labs take their samples from for testing.

When filling the container do not pack down the sample


Document in notes


Documenting EvidencePhotograph the evidence prior to and after collection

– include used gloves and container in photo.If possible, it is good practice to include a permanent

feature (radiator, wall, valve, door casing etc.) in each evidence photograph

When making line drawings – remember to measure location of any movable evidence from two or more fixed, permanent objects

Once collected, the evidence is to be secured and should not be exposed to direct sunlight or intense heat (vehicle a/c)

Documenting EvidencePhotograph the evidence prior to and after collection

– include used gloves and container in photo.If possible, it is good practice to include a permanent

feature (radiator, wall, valve, door casing etc.) in each evidence photograph

When making line drawings – remember to measure location of any movable evidence from two or more fixed, permanent objects

Once collected, the evidence is to be secured and should not be exposed to direct sunlight or intense heat (vehicle a/c)


Evidence before and after collection photosEvidence before and after collection photos


Land marking evidence to be collectedLand marking evidence to be collected


Sampling Procedures for Common Floor Types1. Carpet

Lift any remaining carpet to check underside for odours or staining. Cut a strip of carpet and under pad along odour stain . Chimney roll the carpet strip.

Outside of visible burns or pours- bases of furniture legs, carpet tack boards, behind and beneath floor mouldings and threshold boards are locations to examine.

Provide comparison sample of carpet and pad from unburned area – protected or shielded areas under furniture or distant from pour area. Synthetic carpets are made from petroleum distillates also.

Sampling Procedures for Common Floor Types1. Carpet

Lift any remaining carpet to check underside for odours or staining. Cut a strip of carpet and under pad along odour stain . Chimney roll the carpet strip.

Outside of visible burns or pours- bases of furniture legs, carpet tack boards, behind and beneath floor mouldings and threshold boards are locations to examine.

Provide comparison sample of carpet and pad from unburned area – protected or shielded areas under furniture or distant from pour area. Synthetic carpets are made from petroleum distillates also.


Sampling Procedures for Common Floor Types2. Glazed ceramic tile

Non-porous and poor sampling potential

Samples should be taken of any absorbent material that may have been on top – throw rugs, piles of laundry, boxes – provided they are within the pour pattern area

Locate pre-fire cracks or imperfections in the tiles or grout (may have soot deposits inside crack or crevice). Collect from both edges and the base of the crack. Collect samples of baseboard at the edges of tile surface within the pattern area

Don’t forget to provide comparison sample

Sampling Procedures for Common Floor Types2. Glazed ceramic tile

Non-porous and poor sampling potential

Samples should be taken of any absorbent material that may have been on top – throw rugs, piles of laundry, boxes – provided they are within the pour pattern area

Locate pre-fire cracks or imperfections in the tiles or grout (may have soot deposits inside crack or crevice). Collect from both edges and the base of the crack. Collect samples of baseboard at the edges of tile surface within the pattern area



Sampling Procedures for Common Floor Types3. Concrete

Focus on isolating the locations of absorbent materials stored directly on the concrete floor in the pattern area. Also search pre-fire cracks, expansion seams, floor drains, areas where the liquid accelerant may have spread under pallets or other objects.Common accelerants poured on concrete leave an intermixed mottled black, brown and grey area of staining the corresponds to the shape of the original accelerant pool – may also contain odour and may repel light coat of water

Collection methods include sampling from cracks/seams, direct surface samples and chemical absorbent method Don’t forget to provide comparison sample

Sampling Procedures for Common Floor Types3. Concrete

Focus on isolating the locations of absorbent materials stored directly on the concrete floor in the pattern area. Also search pre-fire cracks, expansion seams, floor drains, areas where the liquid accelerant may have spread under pallets or other objects.Common accelerants poured on concrete leave an intermixed mottled black, brown and grey area of staining the corresponds to the shape of the original accelerant pool – may also contain odour and may repel light coat of water

Collection methods include sampling from cracks/seams, direct surface samples and chemical absorbent method Don’t forget to provide comparison sample


Sampling Procedures for Common Floor Types4. Floor Tiles

Made of vinyl, ordinary ceramic etc.Adhesives or sealant used with these products, and some of the products themselves may be of petrochemical basis

Gently clear and then clean surface of tiles with water rinse until burn pattern can be photographed. Photograph ‘ghost patterns’ where liquid seeped into tile edges and either dissolved or seared the adhesive, leaving a checkerboard like appearance.

Lift edges of tile and break them off about ½ inch from edge of each seam.


Sampling Procedures for Common Floor Types4. Floor Tiles

Made of vinyl, ordinary ceramic etc.Adhesives or sealant used with these products, and some of the products themselves may be of petrochemical basis

Gently clear and then clean surface of tiles with water rinse until burn pattern can be photographed. Photograph ‘ghost patterns’ where liquid seeped into tile edges and either dissolved or seared the adhesive, leaving a checkerboard like appearance.

Lift edges of tile and break them off about ½ inch from edge of each seam.



Sampling Procedures for Common Floor Types5. Linoleum/vinyl sheet floor covering

Made from base of burlap, canvas, or similar material covered by a mixture of linseed oil, gum, cork dust and/or wood flour (linoleum) or thermoplastic polymers of vinyl compounds (vinyl)

Liquid accelerants have 2 effects: (1) the surface will often mollify and begin to dissolve; (2) once ignited, the edge of the accelerant pool will begin to melt, burn and char. As the pool recedes during the fire, the burning and melting will recede with it.

Collection is same as tile – check absorbent materials, then seams and lower portions and joints. Look for pre fire tears, rips or cracks within the pattern, especially near heavy appliances like stoves.For collection cut surface and underlayment – cut and chimney roll


Sampling Procedures for Common Floor Types5. Linoleum/vinyl sheet floor covering

Made from base of burlap, canvas, or similar material covered by a mixture of linseed oil, gum, cork dust and/or wood flour (linoleum) or thermoplastic polymers of vinyl compounds (vinyl)

Liquid accelerants have 2 effects: (1) the surface will often mollify and begin to dissolve; (2) once ignited, the edge of the accelerant pool will begin to melt, burn and char. As the pool recedes during the fire, the burning and melting will recede with it.

Collection is same as tile – check absorbent materials, then seams and lower portions and joints. Look for pre fire tears, rips or cracks within the pattern, especially near heavy appliances like stoves.For collection cut surface and underlayment – cut and chimney roll



Sampling Procedures for Common Floor Types6. Sand/soil floors or building aprons

Soil provides excellent sampling due to high surface to weight ratio and fact that it often remains moist and cool during an abutting fire.

Determine sampling area by lifting top two inches of soil or by pulling tufts of grass or other vegetation with roots to check for odour. Sample the top four to six inches of topsoil from within the trailer or pour area. Include roots if they are dense, surface types

When soil evidence is collected it has to be sent for testing immediately or stored in a fridge or freezer. Bacteria in the soil degrades many common crude oil derivatives and will break down down the remaining residue.


Sampling Procedures for Common Floor Types6. Sand/soil floors or building aprons

Soil provides excellent sampling due to high surface to weight ratio and fact that it often remains moist and cool during an abutting fire.

Determine sampling area by lifting top two inches of soil or by pulling tufts of grass or other vegetation with roots to check for odour. Sample the top four to six inches of topsoil from within the trailer or pour area. Include roots if they are dense, surface types

When soil evidence is collected it has to be sent for testing immediately or stored in a fridge or freezer. Bacteria in the soil degrades many common crude oil derivatives and will break down down the remaining residue.



Sampling Procedures for Common Floor Types7. Wood flooring

Concentrate on seams and joints. Wood has high resistance to lateral heat conductivity. Also search within pour pattern for places where wood grain is vertically aligned, such as in furniture legs or wooden door casings. Liquids are absorbed into the vertical fibres like water to a tree

For tongue & groove or barn board – cut thin slivers from both sides of many adjoining seams within the burn pattern. Place splinters vertically into container.

Sampling Procedures for Common Floor Types7. Wood flooring

Concentrate on seams and joints. Wood has high resistance to lateral heat conductivity. Also search within pour pattern for places where wood grain is vertically aligned, such as in furniture legs or wooden door casings. Liquids are absorbed into the vertical fibres like water to a tree

For tongue & groove or barn board – cut thin slivers from both sides of many adjoining seams within the burn pattern. Place splinters vertically into container.


Sampling Procedures for Common Floor Types7. Wood flooring cont’d

For staircases – cut into seam between tread and riser within the pattern on various steps. Also collect samples from any rubber tread or edge cleats and any remaining carpet.

If stair pattern intersects side of stair, could collect at the edge mouldings or baluster seams

Try to provide comparison sample from same board that suspected pour residue sample was taken from.

Sampling Procedures for Common Floor Types7. Wood flooring cont’d

For staircases – cut into seam between tread and riser within the pattern on various steps. Also collect samples from any rubber tread or edge cleats and any remaining carpet.

If stair pattern intersects side of stair, could collect at the edge mouldings or baluster seams

Try to provide comparison sample from same board that suspected pour residue sample was taken from.


Legal Considerations

Chain of Custody of Physical EvidenceThe value of physical evidence depends on the investigator’s efforts to maintain security and integrity of the evidence from its initial discovery and collection to its examination and testing

At all times after its discovery and collection, evidence should be stored in a secured location and under the sole control of the investigator

Legal Considerations

Chain of Custody of Physical EvidenceThe value of physical evidence depends on the investigator’s efforts to maintain security and integrity of the evidence from its initial discovery and collection to its examination and testing

At all times after its discovery and collection, evidence should be stored in a secured location and under the sole control of the investigator


Steps for Chain of Custody1. Take sample2. Seal and label container3. Either hand over to OPS or secure in your

vehicle4. If no OPS – take evidence to Knoxdale5. There will be an evidence locker at

Knoxdale with an Evidence Log Sheet6. Sign in evidence7. Document each step in notes

Steps for Chain of Custody1. Take sample2. Seal and label container3. Either hand over to OPS or secure in your

vehicle4. If no OPS – take evidence to Knoxdale5. There will be an evidence locker at

Knoxdale with an Evidence Log Sheet6. Sign in evidence7. Document each step in notes



Investigation Report:

Having taken notes throughout your investigation it will become simpler to effectively articulate the steps you have taken to seize evidence and maintain the chain of custody.

Your report will have the following for each exhibit or sample taken:

Investigation Report:

Having taken notes throughout your investigation it will become simpler to effectively articulate the steps you have taken to seize evidence and maintain the chain of custody.

Your report will have the following for each exhibit or sample taken:


Standard Opening for Evidence or Exhibit Collection

Exhibit collectionExhibit collection began at 08:16hrs and was completed by

08:27hrs

Detective Sergeant Christie provided the Mason jars for the taking of exhibits and provided an empty Jar for submission as a control sample. A new set of gloves was used for each sample and the gloves were disposed of afterwards to prevent any contamination.

*Remember to source the containers


Exhibit collectionExhibit collection began at 08:16hrs and was completed by

08:27hrs

Detective Sergeant Christie provided the Mason jars for the taking of exhibits and provided an empty Jar for submission as a control sample. A new set of gloves was used for each sample and the gloves were disposed of afterwards to prevent any contamination.

*Remember to source the containers



Exhibit #1: 09:32hrs exhibit taken by myself, Inspector Donati from closet of ground floor northwest corner bedroom of 1685 Heron Road. 1 burnt piece of Kleenex/tissue paper was placed into an Evidence Bag and sealed. A piece of carpeting and under pad from underneath and around the piece of Kleenex/tissue paper was placed in a clean mason jar. Both Det. Fitzgerald and I photographed the collected exhibit prior to Det. Fitzgerald securing the exhibit and removing it from the scene. Det. Fitzgerald will have the exhibit sent for analysis. See photo P17


Exhibit #1: 09:32hrs exhibit taken by myself, Inspector Donati from closet of ground floor northwest corner bedroom of 1685 Heron Road. 1 burnt piece of Kleenex/tissue paper was placed into an Evidence Bag and sealed. A piece of carpeting and under pad from underneath and around the piece of Kleenex/tissue paper was placed in a clean mason jar. Both Det. Fitzgerald and I photographed the collected exhibit prior to Det. Fitzgerald securing the exhibit and removing it from the scene. Det. Fitzgerald will have the exhibit sent for analysis. See photo P17



Evidence – Physical & Seized for OPSArson Unit

Exhibit #2: At 08:27hrs Det. Sgt. Christie seized the red cap found during my scene examination in the grass on the north side of 25 Plunkett Court for further examination and documentation by the Ottawa Police Ident Unit. See OPS Incident #220649 for further information.

SOCO or IdentExhibit #1: At 22:47hrs I seizes an empty bottle of Nestea Zero

beverage on the step adjacent to the fire scene located at 2199 Regency Terrace. A new set of gloves was used to place the sample into a vinyl Evidence Bag provided by OPS Constable Greenwood. After seizure the exhibit were secured by Constable Greenwood for further processing by Ottawa Police.

Evidence – Physical & Seized for OPSArson Unit

Exhibit #2: At 08:27hrs Det. Sgt. Christie seized the red cap found during my scene examination in the grass on the north side of 25 Plunkett Court for further examination and documentation by the Ottawa Police Ident Unit. See OPS Incident #220649 for further information.

SOCO or IdentExhibit #1: At 22:47hrs I seizes an empty bottle of Nestea Zero

beverage on the step adjacent to the fire scene located at 2199 Regency Terrace. A new set of gloves was used to place the sample into a vinyl Evidence Bag provided by OPS Constable Greenwood. After seizure the exhibit were secured by Constable Greenwood for further processing by Ottawa Police.


Required Documentation:- Field notes that include location at time of

discovery, condition and relationship to the fire investigation

- Photographs of Evidence at discovery and after collection

- Scene Sketches – include measurements and compass direction

- Who collected, in what, who is retaining custody and where it will be stored or sent away

Required Documentation:- Field notes that include location at time of

discovery, condition and relationship to the fire investigation

- Photographs of Evidence at discovery and after collection

- Scene Sketches – include measurements and compass direction

- Who collected, in what, who is retaining custody and where it will be stored or sent away

Documents

Evidence Collection