Q: In a new book, my heroine is framed for a murder that involves a beating through martial arts techniques followed by a fatal push. Are there wound specifics that help authorities determine whether someone was pushed? Could the bruising left by the attacker’s knuckles, hands, or feet be compared to a suspect’s foot or hand?
J. Pearce, Toronto, ON, Canada
A: Pushing almost never leaves bruises that would help distinguish a push from an accidental fall. If the victim were restrained by hand, then bruises that matched the attacker’s fingers might be found on the victim’s arms or legs. It takes a great deal of pressure to restrain someone and this can cause bruising.
The ME might be able to determine whether the bruises and injuries on the victim resulted from a fall or a series of blows with hands or other objects. Rocks and concrete and other objects that the victim might have fallen on can leave bruises just as hands and bats and other weapons do. Often ME can discern a distinctive pattern that would distinguish exactly what made the bruises. Or not. It can go either way.
For example, a rope or a chain used for strangulation or to restrain the victim can leave behind bruises that reveal the braid or link pattern. A blow from a baseball bat or a flat board would leave different bruising patterns—the bat a narrower bruise with diffuse edges and the board a wider bruise with sharper edges. Bite marks often leave bruises that reflect the teeth pattern of the biter and these can sometimes be used to match to a dental impression made from a suspect.
Knuckles could leave a row of round bruises. The size and spacing could be used to rule out certain hands as having delivered the blow while leaving those of a similar size and spacing on the suspect list. The same could be true for the edge of the hand or foot. Either could leave a linear bruise that reflected the thickness of the side of the hand or foot. This would be less clear than would be the knuckles. Again, this could exclude certain suspects.
If the attacker wore a ring with an initial or other distinctive pattern, this pattern could be reflected in a bruise that could be matched to a suspect’s ring.
In your scenario, if knuckle or hand edge bruises were found that did not match the size of your character’s hands then she might be excluded as having made them. If the bruising pattern matched the size of her hands, this would not be conclusive evidence against her but would not remove her from the suspect list.
For more info on trauma patterns, check out HOWDUNNIT:FORENSICS