Detailed analysis from a highly regarded expert in the field of blood pattern analysis. They have wished to remain anonymous but have given permission to write about it in my own words.
ANNOTATED CRIME SCENE IMAGE:
- Assumptions have had to be made with the photographs: Marking which appear to be blood have been taken to be blood, and taken to belong to the victim Julia Wallace.
- Blood spatters radiate towards the camera from the victim’s head: Marked in a green “S” on the image.
- Julia’s mid to upper back is unexpectedly devoid of blood, suggesting that this area was possibly covered by her cardigan or the mackintosh at some point during the attack. Further, the lack of blood run-off suggests she was not upright and instead prone when all strikes to the back of her head occured.
- Blood spatter has traveled towards the paperwork sitting on the chair in the foreground (circled in green).
- Blood to the left of the fireplace is of a “cast-off” pattern, likely from the swinging of the weapon, along with “impact spatter” (impact of the weapon with wet blood).
- Assailant most likely to Julia’s left (our right when viewing the image), somewhere between the round table and chaise lounge.
- Blood on the toilet pan considered to be a drip rather than a clot, falling from above and landing at a right angle.
- To produce the spatter seen, impact with a source of wet blood is needed.
- Final resting place of Julia suggested to be to the right of the fireplace, facing towards the centre of the room, either on her knees or on all fours before falling flat. While on her knees or on all fours her skirt would probably be nearer to the fire and could account for the burning.
- Once flat on the ground, numerous blows were rained onto the back of her head producing the cast-off and impact spatter described.
- Not possible to determine if the attacker was left or right handed.
- Analysis of mackintosh hindered due to the lack of photographs of the patterning upon it. However, the visible portion is clean, which suggests it was not in that position during the attack and has been moved. (Based on witness statements, the mackintosh was initially more underneath Julia, and has evidently been moved aside by the time the photographs were taken).
- Suggests the mackintosh and skirt burning happened at the same time.
- The assailand is expected to have very little if any blood upon them from carrying out this attack.