Detection of fresh blood by luminol and DNA after walking over various substrates

Figures & data

Figure 1. The sole tread of the shoes worn (a); an example stain print left by the shoe after stepping in blood and being sprayed with luminol solution (first step of participant 2 on carpet substrate) (b); and step 17 (step point 2) of the same series, from which DNA was sampled (c). The circled area in C represents the approximate area of the stains sampled for DNA (~4.91cm²).

Table 1. Participants’ measurements and characteristics.

Participant	Height	Weight	Shoe size*	Step size**
1	165 cm	75 kg	7 women’s	44 cm
2	171 cm	60 kg	9 women’s	55 cm
3	155 cm	58 kg	9 women’s	30 cm
4	187 cm	80 kg	11 ½ men’s	65 cm
5	176 cm	71 kg	11 men’s	30 cm

*Shoe sizes are Australian.

**Step size was measured from the distance of step from the tip of the left foot to the heel of the right foot.

Table 2. The number of steps taken by each participant to reach each designated step point (SP).

Participant	Concrete			Carpet			Linoleum
	SP1	SP2	SP3	SP1	SP2	SP3	SP1	SP2	SP3
1	32	37	46	23	28	37	23	28	37
2	12	17	26	30	35	44	15	20	29
3	30	35	44	36	41	50	14	19	28
4	40	45	54	21	26	35	23	28	37
5	15	20	29	32	37	46	16	21	30

SP1 – the fifth last step to show chemiluminescence in the ball of the foot area), SP2 – the first step to show no chemiluminescence at the ball of the foot area, and SP3 – the tenth step to show no chemiluminescence at the ball of the foot area.

Figure 2. Amount of DNA (ng) recovered from each step point (SP) for each floor type.

Table 3. The number of donor alleles (excluding amelogenin) within the profiles at step-points 1, 2 and 3 per floor-type for all 5 participants.

		Number of alleles
Substrate	Point	0	1–3	4–14	15–39	40
	Profile	None	Inconclusive	Partial profile		Full
Concrete	1	4			1
	2	2			3
	3	3	1		1
Carpet	1	1		2	2
	2	1		2	2
	3	1	1	2	1
Linoleum	1				1	4
	2				4	1
	3		1	1	2	1