The famous bra clasp was photographed on the floor of Meredith Kercher’s room on November 2nd, 2007 but collected as evidence on December 18th. It was unaccounted for and “missing in action” for 46 days, a period in which the crime scene (indeed the whole flat) was turned upside-down during undocumented inspections, so much so that it was recovered four or five feet away from where it was originally photographed.
The Y-haplotype testing for the bra clasp showed peaks belonging to at least three unknown male profiles, besides the one attributed to Raffaele Sollecito, a clear indication of contamination.
The prosecutions objection to contamination is the lack of a source of Raffaele Sollecito’s DNA in the flat (except on a cigarette butt), but the same can be said for the three unknown male profiles, which are nevertheless on the bra clasp.
The problem is that an accurate mapping of every possible source of DNA in the flat wasn’t done, otherwise there would be multiple occurrences of two unknown female profiles corresponding to Laura Mezzetti and Filomena Romanelli.
The bra clasp moreover couldn’t be further tested by the independent experts, Professors Conti and Vecchiotti, because it was either intentionally destroyed at worst or stored incorrectly due to incompetence by prosecution expert, Patrizia Stefanoni, who allowed the hooks to rust from storing it in extraction buffer.  See Evidence Destroyed for photos. In other words, the key piece of evidence against Raffaele Sollecito was rendered useless.
Independent Experts Conti-Vecchiotti noted in their report:
- No attempt was made to microscopically identify any cellular material present;
- The DNA quantification kit used is not listed;
- There was only a single amplification of 165B;
- The electroherogram presented made it not possible to independently interpret the results regarding stutter;
- No testing for blood or any other body fluids was conducted;
- The amplification control was not provided;
- The documentation regarding possible contamination of the item, both before and after recovery, is inadequate.
What then does the DNA evidence on the bra clasp mean? It is no surprise that Meredith Kercher would be the primary DNA donor on her bra clasp. Her DNA would be expected to be deposited on the clasps by her touching the clasp and by the clasp presumably having contact with her skin when the bra is worn. The DNA on the bra clasp that is consistent with Sollecito is at a much lower level and there is no information as to what type of cellular material is responsible for the DNA. It is not known when the DNA consistent with Sollecito was deposited on the clasp. Based on the ‘additional’ peaks flagged by Conti and Vecchiotti there may well be DNA from multiple males in low quantity on the bra clasps. It does not seem likely that multiple male individuals would have touched the bra clasp with their hand.
It has to be kept in mind that DNA testing is now extraordinarily sensitive, perhaps to a fault. DNA laboratories go through great lengths to ensure that DNA from analysts or other cases does not end up associated with evidence that is being processed. Laboratories and the tools used are almost obsessively cleaned with bleach solutions, and protocols include many steps to minimize the chance for contamination. Nevertheless, every DNA lab sees contamination at some point. The bottom line is that DNA can be easily transferred, and today’s sensitive DNA tests can detect transfers of low levels of DNA.
The final issue covered in the Conti-Vecchiotti report is the collection of the bra clasps and procedures used at the crime scene. Among the many issues raised was the following:
“The initial position of discovery on the floor of the clasp was not the same after 46 days; and moreover it was touched several times in succession by several operators, after having been collected from the floor, and repositioned again on the floor”
These factors have the potential to have introduced contamination onto the bra clasps. It is unclear how and when the DNA on the bra clasps got there. There are major concerns regarding the collection of the evidence. All things considered, the weight of the evidence of the finding of DNA consistent with Rafaelle Sollecito on the bra clasps is highly questionable particularly since this is the only piece of DNA evidence associating Sollecito with the crime.
The Lab Work
With regards to the few documents related to positive and negative controls submitted during the hearing of 5th September 2011 (controllo neg.doc, controllo pos.doc, I Sample Info REP.36-B.doc, II prova 36-B.doc, II Sample Info REP. 36-B.doc, Rep.165-B.doc), we note that:
1) from the file “I Sample InfoREP.36-B.doc” it can be deducted that the negative control (ID778) and the positive control (ID777) are quality controls relating to the analysis session of exhibit ID771 (trace B of exhibit 36, knife);
2) the electropherograms of these controls were not provided and so it is not possible to evaluate them;
3) Instead the electropherograms of a negative control (ID732) were provided and one positive [control] (ID731) for which, however, it is not possible to determine which session of work it refers, nor which proceedings (they could in reality be controls from another court case);
4) for exhibit 165B-clasp, no controls are provided, neither positive nor negative: to date there is still no evidence that PCR quality controls exist relating to this exhibit;
5) however it is improbable that the controls 731 and 732 refer to the clasp, considering that, if the number of the exhibits is progressive as one would expect, they should be preceding the exhibit 36-B (771), and so before the 13th November 2007; the clasp was instead analyzed from 29th December 2007 onwards.
In conclusion, it can be established that the appealed sentence fell into a serious misrepresentation of a decisive piece of evidence, that, if properly evaluated, would have permitted to ascertain the occurrence of laboratory contamination.
Prosecution expert Patrizia Stefanoni can’t say exactly how much of Raffaele Sollecito’s DNA is alleged to be on the hook but does reveal it’s Low Copy Number (LCN). 1/7 of 1ng = 140pg. LCN being < 200 pg/uL. 
Transcript May 22, 2009 page 108-110
Question – The quantification of the trace on the clasp.
Answer – Utilizing the Applied Biosystems Quantifiler kit.
Question – And what is the quantity, exactly?
Answer – I’m sorry, I don’t understand, the quantity of what? Of the entire DNA sample?
Question – Yes, yes.
Answer – At the moment I don’t have it but, let’s say, it’s a suitable quantity to have it amplified, that’s why it was amplified.
Question – Yes, you know, the two of us have already seen in the preliminary hearing, that one of the things that we point out is the quantity of the trace. I was interested in if this trace was quantified.
Answer – With the appropriate software for the quantification that is practically included with the instrument, in the 7700 that we use.
Question – Yes, what I’m asking you is this: granted that we are talking here, you said it already, with a trace on the hooks, is that correct?
Answer – Yes.
Question – Because there is no DNA that you have attributed to Sollecito on the small piece of cloth, correct?
Answer – Correct.
Question – Nor on the bra.
Answer – Correct.
Question – So given that we are therefore talking about DNA that is only on the hooks I want to know what the quantity was.
Answer – I cannot tell you, numerically I don’t know, certainly is was… since the product of amplification is completely, let’s say a result absolutely of good quality. I suppose that at least in the amplification test tube there was a nanogram of DNA in total.
Question – However, you understand well that this is an assumption of yours. I wanted to know if you were able to give me the documentation of this.
Answer – Ah, the documentation of that quantification, yes, but not now however. Unfortunately, that is, numerically the number that came out of the analyzing software,I don’t have it now.
Question – Are you able, nevertheless, to produce the quantity?
Answer – Yes, the quantity, yes.
Question – So you will be able to tell us how much of a trace there was?
Answer – How much total DNA there was, because there was a mix, I don’t distinguish DNA of the victim quantitatively from the DNA of Sollecito, I can distinguish it… rather, I can make a quantitative relationship between the two DNA only looking at the electropherogram. Therefore, looking at the electropherogram I estimated it to be a 1 to 6 ratio. That is, the victim’s DNA is 6 times more than the DNA of Sollecito, however…
Question – Let’s start by saying this, therefore in the area of the trace found on the hook we have a quantity of DNA attributable to the victim, which is 6 times more than that of Sollecito?
Answer – Yes.
Question – The quantity, however, the number you cannot tell me?
Answer – The total, no, I don’t have it here.
Question: All right. Listen, the quantity of the sample analyzed, that we don’t know, because we don’t know what it was…
Answer: But it was certainly greater than one nanogram, that is certain because that…what makes this electropherogram good is that the peaks, both the principal and the secondary peaks, are all relatively high, quite high, and that kind of result can only be obtained from a quantity of DNA that is at least one nanogram more or less, which is what is advised by the firm that produces [the analysis kit].
Question: But did you repeat the amplification?
Answer: No, the amplification – no.
Question: Why ever not?
Answer: Because I didn’t think it was useful to repeat it.
Question: What is amplification used for?
Answer: It is used to display the genetic zones of interest.
Question: Can it happen that the repetition of amplification can yield different results, different readings of certain peaks?
Answer: No, if the quantity of DNA is sufficient, as in this case, no, the results should be the same.
Question: But we don’t know the quantity of DNA.
Answer: For heaven‘s sake That is –
This excerpt is in regards to the knife but it applies to the clasp as well. At the pre-trial, Stefanoni testifies single amplification LCN DNA results aren’t valid results unless they’ve been repeated.
Transcript October4, 2008 page 22
Question: ….the testing of a trace of this type should be repeated several times to be considered reliable?
Answer: In theory yes.
Question: How many times did you do it?
Answer: In this case only once.
Question: Only once, and therefore in theory why ought it be considered more reliable if one does it several times?
Answer: Because reproducibility of the result is, so to speak, a good standard in any scientific experiment quite apart from forensic genetics, obviously in order to be considered valid a result must be repeatable.
The video below shows how the investigators mishandle this piece of evidence. They pass it around with contaminated gloves and at one point even drop it back on the floor.
Conti and Vecchiotti’s Criticism of the Bra Clasp
From what has been explained above, we can draw the following conclusions about the analytical procedures performed on Exhibit 165B.
– Regarding the nature of the material taken from the item, there does not exist evidence which scientifically confirms the presence of presumed flaking cells. Hence the hypothesis formulated by the Technical Consultant about the nature of the material taken from Exhibit 165B is wholly arbitrary in that it is not supported by objective findings;
– From the electrophoretic graph relative to the autosomic STRs, we can assert that relative to the markers D8S1179, D21S11, D19S433, D5S818, there was an erroneous interpretation of the peaks present in the electrophoretic graph in that peaks were considered stutter whose height was above 50 RFU (D19S433 peak 14↑54), exceeded the threshold of 15% of the major allele (D8S1179, D21S11, D5S818), or were not in stutter position (D5S818), and thus should have been considered alleles. It follows from this that in the DNA extracted from Exhibit 165B are present several minor contributors that were not revealed by the Technical Consultant;
– The electrophoretic graph relative to the Y chromosome markers shows, besides the peaks indicated in the RTIGF as alleles, the presence of additional peaks with heights that exceed the threshold of 50 RFU which, despite not being in stutter position, were not taken into consideration by the Technical Consultant. It follows from this that in the DNA extracted from Exhibit 165B are present several minor contributors which were not revealed by the Technical Consultant, confirming what was already observed in the electropherograms of the autosomic STRs.
– We find that the Technical Consultant arrived at this restrictive conclusion (presence of only two individuals: victim and Raffaele Sollecito) following an incorrect interpretation of the autosomic STRs as a result of having disregarded the recommendations of the ISFG concerning the correct interpretation of mixtures, recommendations which, had they been followed, would have allowed one to conclude that several minor contributors were present in the trace besides the victim’s profile (major contributor). Hence we agree with Dr. Stefanoni’s statement regarding “the extrapolation of a genetic profile deriving from a mixture of biological substances belonging to at least two individuals, at least one of male sex” but we cannot accept the conclusion stating that “the genetic profile is compatible with the hypothesis of a mixture of biological substances (presumably flaking cells) belonging” only ”to Raffaele Sollecito and to Meredith Susanna Cara Kercher” insofar as, from what has been explained above, a mixture is present in which several contributors of male sex are present (a circumstance supported by the electropherogram relative to the Y chromosome, where several alleles are clearly present which, despite being particularly evident, were not taken into consideration by the Technical Consultant);
– The item was recovered 46 days after the crime, in a context highly suggestive of environmental contamination. The risk of incorrectly interpreting such environmental contaminants from dust could have been minimized only by taking the care [avendo l’accortezza] to institute extremely stringent control procedures, including the analysis of extracts from sterile cotton swabs soaked with sterile buffer passed on ambient surfaces to take samples of dust, a procedure which was not carried out;
– Taking into account what has been explained relative to the inspection methods, having seen the documentation in the record, and in particular the DVD of the filmed investigation of the scene [indagini di sopraluogo], the official photos of the Scientific Police, and the statements made in court, we find that the universally noted inspection procedures and correct protocols of collection and sampling of items were not applied on Via della Pergola, even [those designed] to minimize environmental contamination and contamination from handling. From this it follows that it cannot be ruled out that the results obtained from Exhibit 165B derive from contamination phenomena in any phase of the collection and/or handling of the item.
Additional DNA Profiles on the Bra Clasp
What The Court-Appointed Independent Experts Concluded:
It follows from this that several minor contributors of male sex are present in the DNA extracted from Exhibit 165B, confirming what was already observed in the electropherogram of the autosomic STRs and which was not revealed by the Technical Consultant.
Thus we agree with Dr. Stefanoni’s assertion regarding “the extrapolation of a genetic profile deriving from a mixture of biological substances belonging to at least two individuals, at least one of male sex” but we cannot accept the conclusion stating that “the genetic profile is compatible with the hypothesis of a mixture of biological substances (presumably flaking cells) belonging” only ”to Raffaele Sollecito and Meredith Susanna Cara Kercher“.
We find that the Technical Consultant arrived at this conclusion restricted to two individuals (Meredith Kercher and Raffaele Sollecito) following an incorrect interpretation of the electropherograms of the autosomic STRs, as a result of disregarding the recommendations of the ISFG concerning the correct interpretation of mixtures (“Recommendation 6: If the crime profile is a major/minor mixture, where minor alleles are the same size (height or area) as stutter of major alleles, then the stutters and minor alleles are indistinguishable. Under these circumstances, alleles in stutter position that do not support H_p [the prosecution’s hypothesis] should be included in the assessment”) and point 7 of the aforementioned ISFG recommendations (Point no. 7: Drop-out: “The consideration on drop-out is analogous to that on stutter“). Had these recommendations been followed, they would have allowed one to reach the conclusion that several minor contributors were present in the trace besides the victim (major contributor).
The latter assertion is supported by the electropherogram relative to the Y chromosome, where several alleles are present that, despite being particularly evident, were not taken into consideration by the Technical Consultant.
The genetic profile thus derives from a mixture of unidentified biological substances (it will be recalled that no test was performed with a view toward revealing the presence of flaking cells, and so the claim is without scientific basis), whose larger component is represented by the DNA of the victim and whose smaller component is represented by DNA from several individuals (cf. autosomic STRs) of male sex (cf. Y chromosome), of which one of the Y haplotypes corresponds to the Y haplotype of Raffaele Sollecito
Regarding the reliability of the item with specific reference to “possible contamination“, we find it appropriate to examine the means by which and circumstances under which Exhibit 165B was acquired.
The item was recovered 46 days after the crime, in a context highly suggestive of environmental contamination.
The DNA obtained, though sufficient in quantity to permit analysis, does not satisfy the minimum quality requirements, due to the evidence of environmental contamination.
Various peaks (cf. table of autosomic STRs and Y-chromosome haplotype) which should have been considered alleles until proven otherwise, were not taken into consideration in the analyses; yet their presence was indicative of the fact that, besides Kercher and Sollecito, other unidentified individuals were represented in the genetic traces found at the crime scene. In this regard, it was necessary to proceed to further amplifications of the extracted DNA in order to confirm the presence of the various haplotypes present at the crime scene — something which was not done, even though a sufficient amount of extracted material was available (cf. SAL: 50 μL of extracted material).
Furthermore, the documentation regarding possible contamination of the item, both before and after recovery, is inadequate. The mere fact that the amplification control — which was not provided — was negative is not enough to rule out environmental contamination of the item previous to the extraction and amplification of the DNA. It would have been necessary to obtain the allele profiles present in the surrounding environment.
The Bra Was Ripped Off Not Cut
The prosecution tried to say the bra clasp was cut off with a 2nd knife. Professor Vinci showed the bra itself was ripped off Meredith in a rage attack. See his report below.
|Hellmann Report – Expert Review 165b||Italian – English||Professor Tagliabracci DNA Report||Italian|
|Jul 18, 2009: Expert Testimony – Professor Adriano Tagliabracci||Italian||The Conti-Vecchiotti Report||Italian – English|
|Sep 14, 2009: Expert testimony – Professor Adriano Tagliabracci||Italian||Professor Vinci’s Bra Clasp Report||Italian|
|Jul 25, 2011 Expert Testimony – Conti-Vecchiotti Testimony||Italian||Bra clasp test results & e-grams||Download|
|May 22, 2009 Patrizia Stefanoni – Forensics Presentation||Italian||Scientific Police bra clasp images||Download|
There were two clasps, both lacking grommets [senza l’occhiello di tenuta della controparte], with extended parts of red-brownish color, others of reddish color; whiteish elements were also partially in evidence.
One of the clasps was recognizable in its original form, with the characteristic square upon which the corresponding round-edged hook is sewn; the other no longer had any kind of shape, as it was so completely deformed as to have been inserted into the first [clasp], with which it was partially fused due to the presence of rust; separation of the two elements would involve the fragmentation of certain rusted components.
 Validity of Low Copy Number Typing and Applications to Forensic Science Bruce Budowle, Arthur J. Eisenberg, Angela van Daal
DNA and the law in Italy: the experience of “the Perugia case” by Carla Vecchiotti and Silvia Zoppis. Reviewed by David Balding and Joelle Vuille
Understanding The Independent DNA Experts’ Report In The Amanda Knox Case (Part2) MBA DNA Consulting