BPA Expert

Authoritative forensic expert testimony in the disciplines of DNA, bloodstain pattern analysis (BPA), STRmix and biological fluids.

A preliminary review can be a useful step in assessing the broad strengths and weaknesses of a particular matter. This process can also identify documentary and any further evidence requirements.

I rigorous interrogation of the evidence will uncover underlying issues and determine the most appropriate pathway towards reviewing and reporting the matter.

Certain complex matters benefit from a draft report, which can open areas for discussion with Counsel, and potentially allow for defence to approach the prosecution.

Following a thorough evaluation of the evidence, a DNA expert report will be issued in accordance with the expert witness code of conduct. The report will be suitable for submission in evidence.

Preparations with Counsel are often conducted, such that the probative value of the evidence is weighed effectively and persuasively at Voir Dire, should such a hearing be required.

Extensive preparations are generally conducted in anticipation of substantive hearing. Which may include cross examination and evidence in chief scenarios specific to the matter .

Blood stain Pattern ANALYSIS

Bloodstain pattern analysis (BPA), is a forensic science developed to assess blood evidence, in order to form opinions as to pertinent factors within the crime scene.

As distinct from identification, the bloodstain pattern analyst considers the principles of biology, physics and mathematics in an effort to consider blood origin, wound cause, bloodletting directionality, perpetrator location, victim location, event timeline and factors subsequent to the event.

Given the often complex nature of serious crime scenes, our work involving Bloodstain pattern analysis regularly occurs in conjunction with DNA and other biologic fluids identification and review.

Bloodstain pattern analysis is broadly a subjective science, which commonly and correctly seeks to consider the limitations as to what this forensic science is able to specifically consider in a robust manner.

Bloodstain pattern analysis (BPA), is a forensic science developed to assess blood evidence, in order to form opinions as to pertinent factors within the crime scene.

As distinct from identification, the bloodstain pattern analyst considers the principles of biology, physics and mathematics in an effort to consider blood origin, wound cause, bloodletting directionality, perpetrator location, victim location, event timeline and factors subsequent to the event.

Given the often complex nature of serious crime scenes, our work involving Bloodstain pattern analysis regularly occurs in conjunction with DNA and other biologic fluids identification and review.

Bloodstain pattern analysis is broadly a subjective science, which commonly and correctly seeks to consider the limitations as to what this forensic science is able to specifically consider in a robust manner.

BPA Error rate

The error rate of bloodstain pattern analysis and the reliability of bloodstain expert evidence has been the subject of significant scientific and jurisdictional attention. The National Academy of Sciences released a report in 2009 stating that conclusions were often “more subjective than scientific” and open to “context bias”.
Further, a study of 75 BPA analysts in 2021 found that 11% erroneously identified bloodstain pattern (classification) types.
Our experience is that bloodstain pattern analysis can be highly useful in certain circumstances, though great care and skill must be applied to the evidence.

Conclusivity

The reliability and conclusively of bloodstain pattern analysis strongly rests within the extent and nature of propositions that one is seeking to consider.
Bloodstain pattern analysis is largely a subjective field, with the analyst seeking to answer questions about the manner and sequence of events, through the resultant bloodstains.
The analyst must exercise great caution and discretion when setting parameters as to what the evidence is fundamentally capable of supporting.
For example, transfer stains have been erroneously reported as impact spatter, having catastrophic outcomes for the justice system.

Evidence Tampering

Crime scene evidence tampering is frequently encountered when inspecting bloodstain pattern evidence.
Rudimentary weapon and hand wipe down, can extend through to sophisticated efforts to chemically remove bloodstain and DNA evidence.
Clean up attempts can drastically alter the bloodstain patterns, risking erroneous interpretation.  An experienced analyst should identify clean-up efforts through interpretation of altered bloodstains such as wipes and swipes, and the presence of voids in patterns.
Bloodstaining and DNA are readily removed during laundering, however residual deposits are frequently trapped in areas such as stitching and zippers.

Luminol

Luminol is a chemical used in forensic investigation, which emits light (luminesce) upon contact with blood. It is highly useful to detect blood that cannot be visually observed, and where crime scene clean-up is suspected.
Luminol has a known propensity to react with some cleaning products including bleach.
Where luminol reactions are observed, confirmation of blood should be obtained through confirmatory testing. The observation and recovery of obscured and concealed blood, may require extensive physical searching of crevices. and would subsequently be utilised to conduct DNA testing for consideration of identity.

BPA Contamination

Contamination or crime scene alteration occurs frequently, through offender efforts to clean up, or unintended acts.
Homicides and serious assaults often involve first responders such as paramedics and police officers seeking to preserve life, which invariably result in alteration or production of new bloodstain patterns, for example through CPR attempts.
Insect activity can occur, with flies feeding on blood and regurgitating it to new locations, with this ‘fly speck’ testing positive for blood and having the appearance of blood spatter.
Skilled and realistic assessment of the crime scene can help establish events.

Crime scene examination

Accurate crime scene examination is crucial to bloodstain pattern analysis.
Meticulous recording of the bloodstain patterns through extensive photography and note taking is required for thorough evaluation and review of bloodstain patterns.
BPA often invokes the assumption that all reddish/brown visible staining is the consequence of the bloodshed event in question.  A robust assumption in this regard can only be evidenced once sufficient testing of the staining has established that the stain is in fact blood.
Bloodstain review is commonly conducted upon high resolution photographs.
We can advise and conduct a physical crime scene examination should it be required.
Error rate

BPA Error rate

The error rate of bloodstain pattern analysis and the reliability of bloodstain expert evidence has been the subject of significant scientific and jurisdictional attention. The National Academy of Sciences released a report in 2009 stating that conclusions were often “more subjective than scientific” and open to “context bias”.
Further, a study of 75 BPA analysts in 2021 found that 11% erroneously identified bloodstain pattern (classification) types.
Our experience is that bloodstain pattern analysis can be highly useful in certain circumstances, though great care and skill must be applied to the evidence.
Conclusivity

Conclusivity

The reliability and conclusively of bloodstain pattern analysis strongly rests within the extent and nature of propositions that one is seeking to consider.
Bloodstain pattern analysis is largely a subjective field, with the analyst seeking to answer questions about the manner and sequence of events, through the resultant bloodstains.
The analyst must exercise great caution and discretion when setting parameters as to what the evidence is fundamentally capable of supporting.
For example, transfer stains have been erroneously reported as impact spatter, having catastrophic outcomes for the justice system.
Tampering

Evidence Tampering

Crime scene evidence tampering is frequently encountered when inspecting bloodstain pattern evidence.
Rudimentary weapon and hand wipe down, can extend through to sophisticated efforts to chemically remove bloodstain and DNA evidence.
Clean up attempts can drastically alter the bloodstain patterns, risking erroneous interpretation.  An experienced analyst should identify clean-up efforts through interpretation of altered bloodstains such as wipes and swipes, and the presence of voids in patterns.
Bloodstaining and DNA are readily removed during laundering, however residual deposits are frequently trapped in areas such as stitching and zippers.
Luminol

Luminol

Luminol is a chemical used in forensic investigation, which emits light (luminesce) upon contact with blood. It is highly useful to detect blood that cannot be visually observed, and where crime scene clean-up is suspected.
Luminol has a known propensity to react with some cleaning products including bleach.
Where luminol reactions are observed, confirmation of blood should be obtained through confirmatory testing. The observation and recovery of obscured and concealed blood, may require extensive physical searching of crevices. and would subsequently be utilised to conduct DNA testing for consideration of identity.
Contamination

BPA Contamination

Contamination or crime scene alteration occurs frequently, through offender efforts to clean up, or unintended acts.
Homicides and serious assaults often involve first responders such as paramedics and police officers seeking to preserve life, which invariably result in alteration or production of new bloodstain patterns, for example through CPR attempts.
Insect activity can occur, with flies feeding on blood and regurgitating it to new locations, with this ‘fly speck’ testing positive for blood and having the appearance of blood spatter.
Skilled and realistic assessment of the crime scene can help establish events.
CRIME SCENE

Crime scene examination

Accurate crime scene examination is crucial to bloodstain pattern analysis.
Meticulous recording of the bloodstain patterns through extensive photography and note taking is required for thorough evaluation and review of bloodstain patterns.
BPA often invokes the assumption that all reddish/brown visible staining is the consequence of the bloodshed event in question.  A robust assumption in this regard can only be evidenced once sufficient testing of the staining has established that the stain is in fact blood.
Bloodstain review is commonly conducted upon high resolution photographs.
We can advise and conduct a physical crime scene examination should it be required.

BLOODSTAIN PATTERN ANALYSIS QUESTIONS

Bloodstain pattern analysis

Bloodstain pattern analysis uses the physical properties of blood, physics (including projectile motion and fluid dynamics) and mathematics (geometry, distance and angles) to interpret bloodstains and recreate the actions that caused them.

Conducting BPA

Analysts assess the appearance, distribution, size, range, shape and spread of bloodstains to interpret the event.

Using photographs to conduct BPA

High resolution photographs can be used to conduct BPA, but the photographs must be taken in a manner that facilities interpretation.

Error rate

A study in 2023 demonstrated that on average BPA analysts incorrectly categorised bloodstains 11% of the time.

Bloodstain pattern analysis - terms

Bloodstain

A deposit of blood on a surface.

Bloodstain pattern

A grouping or distribution of bloodstains that indicates through regular or repetitive form, order, or arrangement the manner in which the pattern was deposited.

Altered stain

A bloodstain with characteristics that indicate a physical change has occurred.

Angle of impact

The acute angle (alpha), relative to the plane of a target, at which a blood drop strikes the target.

Area of origin

The space in three dimensions to which the trajectories of spatter can be utilized to determine the position of the spatter producing event.

Backspatter pattern

A bloodstain pattern resulting from blood drops which can be produced when a projectile creates an entrance wound.

Cast off pattern

A bloodstain pattern resulting from blood drops released from an object due to its motion.

Cessation pattern

A bloodstain pattern resulting from blood drops released from an object due to its abrupt deceleration.

Directionality

The characteristic of a bloodstain that indicates the direction blood was moving at the time of deposition.

Drip pattern

A bloodstain pattern resulting from a liquid that dripped into another liquid, at least one of which was blood.

Drip stain

A bloodstain resulting from a falling drop that formed due to gravity.

Drip trail

A bloodstain pattern resulting from the movement of a source of drip stains between two points.

Expiration pattern

A bloodstain pattern resulting from blood forced by airflow out of the nose, mouth, or a wound.

Flow pattern

A bloodstain pattern resulting from the movement of a volume of blood on a surface due to gravity or movement of the target.

Forward spatter pattern

A bloodstain pattern resulting from blood drops which can be produced when a projectile creates an exit wound.

Impact pattern

A bloodstain pattern resulting from an object striking liquid blood.

Perimeter stain

An altered bloodstain which consists of its edge characteristics, the central area having been partially or entirely removed.

Pool

A bloodstain resulting from an accumulation of liquid blood on a surface.

Projected pattern

A bloodstain pattern resulting from the ejection of blood under hydraulic pressure, typically from a breach in the circulatory system.

Satellite stain

A smaller bloodstain that originated during the formation of the parent stain as a result of blood impacting a surface.

Saturation stain

A bloodstain resulting from the accumulation of liquid blood in an absorbent material.

Spatter stain

A bloodstain resulting from an airborne blood drop created when external force is applied to liquid blood.

Splash pattern

A bloodstain pattern created from a large volume of liquid blood falling onto a surface.

Swipe pattern

A bloodstain pattern resulting from the transfer of blood from a blood-bearing surface onto another surface, with characteristics that indicate relative motion between the two surfaces.

Transfer stain

A bloodstain resulting from contact between a blood-bearing surface and another surface.

Void

An absence of blood in an otherwise continuous bloodstain or bloodstain pattern.

Wipe pattern

An altered bloodstain pattern resulting from an object moving through a preexisting wet bloodstain.

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