Examination of Firearms Review: 2007 to 2010 - Interpol

example, Tanaka [158] worked on measurement on the characteristics of the voltage at
the surface of the film covering the document.
Yaraskavitch [159] et al used a similar approach, concluding, among others, that a
period of charge decay before image development is not required when operating in
optimal regime, which is in opposition with previous findings (Seward 1998).
Nic Daéid [160] et al, worked more precisely on the ESDA (F&F) and its cascade
developer. Their results showed that “humidification of the cascade developer doesn’t
have advantage over storage in a normal environment”. They also found that “200 g of
cascade developer gives good quality results for up to 30 traces”.
Tolliver et al [163], underlined a very important matter, which is “the potential of the
Electrostatic Detection Device (EDD) serving as a source for transfer of DNA”. Indeed, it
is quasi impossible to prevent cross contamination when using this kind of device. It is
really important to know about this issue in the sample analysis process especially when
DNA research is done by external labs.
14. Quality assurance
We found only one reference dealing with quality assurance directly applied to
Questioned document matters.
This reference is from Ottiker [202] and raises the problem of the choice of reference
standard for handwriting examination. In his precise case it is ISO/IEC 17020 and
ISO/IEC 17025 that are discussed. He concluded stating that “when applying ISO
17025 for comparative analysis, the expert is considered to be the measurement
instrument and the ultimate goal is to validate the result of this instrument (the opinion
given by the expert). Based on this statement, the method validation as required by ISO
17025 consists in verifying the expert’s competence, which is exactly what ISO/IEC
17020 mainly asks for competence assurance”.
Thus, whatever the choice of the quality standard is, it is absolutely necessary for a
Questioned Document Examination lab to follow an official standard which is often
recommended by the international forensic networks. For example ENFSI recommends
ISO/IEC 17025 and/or 17020. Moreover these international networks often propose
technical standards regarding document and handwriting analysis. Thus, before,
creating new methods, it is necessary to be informed of all existing standards and
papers that can be a good basis to avoid bad practices and to facilitate the process of
accreditation. An ideal situation, would be to take part in the technical work of these
networks.
Moreover a good way for a laboratory to demonstrate the quality of its work or even to
prove its commitment to continuous improvement is to take part in the various available
proficiency testing programmes like the ones from CTS and ST 2 AR (both handwriting
and documents , EDEWG (documents) and ENFHEX (Handwriting).
360