Introduction
18.1. Y7 was not found when the bathroom door-frame was dusted with aluminium powder on 9 January but was found when the scene of crime officers used black powder on 14 January.1 One of the SOCOs, Mr Ferguson was critical of the decision to start with aluminium powder2 and this gave rise to two issues concerning proper practice for scene of crime examination. The first was the extent to which the selection of the powder to be used can affect the discovery of prints and the second was the acceptability of a sequential application of different powders. The substantive questions to which those issues lead are whether any inference can be drawn as to the date when Y7 was placed on the door-frame and, assuming it to have been there on 9 January, whether a clearer impression of the mark would have been obtained had the examination begun with black powder. That was the crux of Mr Ferguson's e-mail to Mr McKie in January 2000:
"Had the hall been examined in black powder at the start this whole sorry affair would never have happened. At least that was how I felt at the time. The print which was mistakenly identified as Ms McKie's may or may not have been there. It may have been clearer and then possibly not mistakenly identified."3
18.2. The inference, if any, to be drawn in relation to the date of placement of the mark Y7 is discussed in Chapter 3. This chapter considers whether the scene of crime examination was consistent with acceptable practice in relation to the detection of Y7.
The scene of crime examination for marks
18.3. Mr Ferguson explained that his training was that black powder was best suited to white door facings4 and he thought that using aluminium powder on the door-frame was unusual because aluminium powder was more suited for other surfaces such as glass.5 Ultimately, though, he acknowledged that it came down to the individual choice of the scene of crime examiner.6 Mr Thurley was finding marks with the aluminium powder and he did not say anything to Mr Thurley at the time about the use of that powder.7
18.4. Mr Kerr, the detective in charge at the scene, told the Inquiry that he would have expected black powder to have been used. Though not an expert he had had some training on obtaining fingerprint evidence, and had seen aluminium powder used on gloss surfaces before but not at major incidents. He recalled heated debate primarily instigated by Mr Moffat about this.8
18.5. The decision to use aluminium powder was made by Mr Thurley. He was the head of the team of SOCOs on site.9 He accepted that the facts that the area around the bathroom door was heavily nicotine stained and affected by the presence of steam might have called for the use of black powder. However, he said that because a large number of prints were being obtained he was happy to continue using aluminium powder.10 It was the least destructive and using it first gave the option of using other powders and chemicals later.11 He had no recollection of any discussion or disagreement about the use of aluminium powder.12
18.6. Mr Moffat, who began dusting on 10 January, started looking for marks upstairs using black powder but after learning that Mr Thurley wanted everyone to use it and discussing the matter with him he switched to aluminium.13 In his oral evidence he referred to the SOCOs being upset that they were not being allowed to use black powder14 but he accepted that the choice was personal because both give good results.15
18.7. Mr Hunter commented that there was a generational difference among officers, with younger officers tending to use black powder first because it gave instant results and older officers using aluminium first and then black.16 Mr Ferguson had less than two years' experience in 1997.17 Mr Hunter had sixteen years' experience and thought that the use of aluminium powder first was a reasonable choice because it left other options open.18
18.8. Mr Hogg, Head of the Identification Bureau at the time, said that he was happy with the use of either powder. He confirmed that this was a matter on which some officers had a personal preference but because black could be used after aluminium his position was that in the event of doubt an officer should start with aluminium and would normally continue to use it if he was getting results with it.19
18.9. Mr Hunter said it was not usual to be told what powder to use20 and Mr Hogg's evidence would also suggest that, because the powder to be used was a matter of personal preference, it would have been unusual for an instruction to have been given. That is reinforced by the fact that he said usually it was a case of using one powder or the other, rather than both. Prior to the case of Marion Ross he had not been aware of a case where a fingerprint had been detected with black powder where aluminium powder had totally missed it but he was aware of the use of black powder 'improving' a poor quality mark that had been partially revealed by aluminium powder.21 However, the report to the procurator fiscal dated 26 February 1997 by Mr Orr confirms that there was a practice in serious cases of repeating examinations using black powder.22
Scientific advice on powder selection
18.10. The Inquiry had the benefit of evidence from two Home Office scientists, Mr Kent and Dr Bleay, in relation to the suitability of the choice of aluminium powder for the initial examination and also regarding sequential examinations.
18.11. Mr Kent, whose research team produced the Home Office advice available in 1997,23 said that the Home Office issued rigid instructions in other areas of fingerprint chemistry but because of the limited statistical data on the performance of powders they gave guidelines only. He mentioned further research work done since his retirement from HOSDB. 24 Dr Bleay referred the Inquiry to the Scene of Crime Handbook from 199325 and the Inquiry had the opportunity to look at an updated leaflet 'Fingerprint Powders Guidelines' dated March 2007.
18.12. The 1993 handbook, as quoted by Dr Bleay,26 noted that the effectiveness of powdering was variable depending on the chemical and physical nature of the powder, the type of applicator, the care and expertise of the operator and the nature and condition of the surface being examined. It advised examiners to use the powder most sensitive to the latent fingerprint deposit. It indicated that with deposits such as furniture polish or general grime, a less sensitive powder might sometimes be more effective and reduce the chances of clogging or filling in ridge detail.
18.13. Mr Kent suggested that probably most UK police forces at that time were using aluminium as the first powder at a crime scene provided that there were no other problems, no other issues with regard to the crime scene. He added that on greasy surfaces, such as in a kitchen, aluminium powder would tend to smear and the scene of crime officer might choose a granular powder in preference.27 However, it was thought that metallic flake powders such as aluminium were more sensitive than granular black powder, and where sensitivity was important aluminium was probably the powder of choice28 but it was difficult to be categoric because it was difficult to say precisely what technique will work under any possible circumstances.29
18.14. Dr Bleay emphasised that one also had to take into account the expertise of the scene of crime officer. An officer's operational experience might make the officer believe that a certain type of powder was going to be more effective on a certain type of surface. He advised the Inquiry that the choice of aluminium flake as an initial powder treatment was not inconsistent with the advice available in 1997.30
18.15. The March 2007 leaflet 'Fingerprint Powders Guidelines' contains guidelines based on extensive trials on a range of surfaces and refers to full trial reports (from 2004 and 2006) and other material. A note indicates that aluminium flake, black granular, black magnetic and magneta flake powder performed similarly on many smooth surfaces. It continues: "However it is widely considered that flake powders are more sensitive than granular ones although little evidence is available in the literature to back this up." Black granular powder is noted as suitable for use on some smooth surfaces only. Aluminium flake powder is noted to be the most effective powder on glass but, as it shows similar performance to alternative powders on other smooth surfaces "it may still be the powder of choice as it is easy to apply and develops good contrast marks on most smooth surfaces."31
Scientific advice on sequential applications
18.16. Dr Bleay stated that sequential powdering was also not inconsistent with guidance at the time. It may develop more marks overall but even as at 2009, when Dr Bleay gave evidence, not a lot was known about the effects of sequential examination.32
18.17. Mr Kent confirmed that a number of people did carry out sequential examinations but it was not a matter on which a significant amount of research had been carried out. Anecdotally he had people tell him that they had found better fingerprints after using black powder after aluminium and vice versa but he had not seen photographic proof of this.33
18.18. Dr Bleay thought there was potential for more research in this area.34 He had observed in a "pseudo-operational situation" that marks could come up with black granular powder after aluminium powder. He carried out a brief experiment using marks from 50 donors and found that 5-10% of marks were first disclosed on a second examination with black powder.35
Conclusions on initial powder selection and sequential examinations
18.19. My conclusion is that it was reasonable for Mr Thurley to have decided to use aluminium powder and that his choice did not conflict with the Home Office guidelines of the time.
18.20. I also conclude that there is no evidence to support any suggestion that the sequence of using black granular powder after aluminium powder was inappropriate, or in conflict with any guidance available at the time.
1. See Chapter 3
2. See Chapter 3 paras 3 and 87
3. CO_1327
4. Mr Ferguson 10 June pages 75-76
5. FI_0010 para 20 Inquiry Witness Statement of Mr Ferguson
6. Mr Ferguson 10 June page 75
7. Mr Ferguson 10 June pages 74ff, 82 and FI_0010 paras 19-21 Inquiry Witness Statement of Mr Ferguson
8. Mr Kerr 18 June pages 34-36 and FI_0044 paras 20, 50 Inquiry Witness Statement of Mr Kerr
9. Mr Hunter 10 June page 108
10. FI_0037 paras 34-35 Inquiry Witness Statement of Mr Thurley and Mr Thurley 10 June page 29ff
11. Mr Thurley 10 June pages 24-25
12. FI_0037 para 35 Inquiry Witness Statement of Mr Thurley and Mr Thurley 10 June page 29
13. Mr Moffat 11 June pages 36-41 and FI_0003 para 31 Inquiry Witness Statement of Mr Moffat
14. Mr Moffat 11 June page 36
15. FI_0003 para 36 Inquiry Witness Statement of Mr Moffat
16. Mr Hunter 10 June pages 109-110
17. FI_0010 paras 1, 21 Inquiry Witness Statement of Mr Ferguson and Mr Ferguson 10 June page 82
18. Mr Hunter 10 June pages 108-109 and FI_0042 paras 2, 11 Inquiry Witness Statement of Mr Hunter
19. Mr Hogg 17 June pages 9-10
20. FI_0042 para 11 Inquiry Witness Statement of Mr Hunter
21. FI_0034 para 26 Inquiry Witness Statement of Mr Hogg
22. See Chapter 8 para 9
23. Mr Kent 7 July page 24
24. Mr Kent 7 July pages 27-28
25. Dr Bleay 16 November page 138
26. Dr Bleay 16 November pages 138-140
27. Mr Kent 7 July page 25
28. Mr Kent 7 July pages 24-25
29. Mr Kent 7 July pages 26-27
30. Dr Bleay 16 November pages 137-141
31. Bandey H. Fingerprint Powders Guidelines. Home Office Scientific Development Branch, 2007, 09/07 URL: http://tna.europarchive.org/20100413151426/http://scienceandresearch.homeoffice.gov.uk/hosdb/publications/fingerprint-publications/09-07_-_Fingerprints_Powder5807.html?view=Standard&pubID=454823
32. Dr Bleay 16 November pages 140-141
33. Mr Kent 7 July pages 29-30 and see pages 161-162
34. Dr Bleay 16 November page 141
35. Dr Bleay 16 November pages 142-143