Glass, paint and contact traces

 First Forensic are experts in contact trace evidence - glass, paint, fibres, security dyes and particulate materials. Our Contact trace team has extensive experience in the field of forensic chemistry. The team is led by Karen Wade who has many years experience reporting a wide range of forensic chemistry cases.

The forensic analysis and comparison of these materials can be utilised in a variety of different investigations and circumstances

 Our trace evidence service includes

  • Advice and expertise on the analysis and interpretation of a wide range of particulate materials
  • Assessment of the "commoness" of a given sample of glass
  • Review of the methods, procedures and results obtained by the prosecution
  • Re-assessment of the original interpretation of the significance of any findings
  • Identification and comparison of a diverse range of "unknown" materials using a range of microscopical and instrumental techniques
  • Review of the previous findings, in the light of additional information

 

Glass examinations, comparisons and interpretation

The presence of matching glass at the scene of an incident can provide strong supporting evidence, and likewise the absence of glass in certain circumstances can provide evidence to support the view that a person was not involved in an incident. This type of evidence can prove invaluable when distinguishing between the prosecution and defence versions of events.


When a pane of glass breaks, small fragments of glass are ejected backwards as well as forwards, typically for up to 2 or 3 metres. These fragments can land and become lodged in the tools, clothing and/or hair of the person breaking the window. So not only is it possible to identify if a suspect was present at the crime scene, you can even determine from which side a window was broken.

When glass fragments are examined by a suitably experienced forensic scientist it may be possible to distinguish between glass from different sources e.g. different windows and different types such as bottle and window glass.

Broken glass can also provide other crucial forms of evidence such as fingerprints, footwear marks, blood, hairs or fibres from clothing which have been caught on the sharp edge of the glass. Using our specialist skills we can analyse this evidence and help to uncover vital information. For more information on the forensic examination and comparison of glass samples, click here.


Paint examinations and comparisons

Paint is a material in widespread use as a decorative and protective finish, the most common usage being on vehicles and domestic items. The tern “Paint” is a generic one which includes lacquers, varnishes and emulsions. Almost all paints comprise a pigment (or pigments) to give colour, extenders to bulk out the pigment, a resin or polymer to bind the particles of pigment and extender together, and a liquid vehicle. Over a period of time, household surfaces may be painted numerous times, which can result in a “unique” combination of layers of paint. For more information on the forensic examination and comparison of paint samples, click here.

We also have expertise in a wide range of other contact traces including:

  • Security dyes, including "cash in transit" and Smartwater
  • Building debris examinations, comparisons and interpretation
  • Drugs
  • Review of Over the Prescribed Limit (OPL) cases,
  • Alcohol technical defence and assessment of pre and post accident drinking.
  • We can carry out identifications and comparison of a wide range of materials using a range of microscopical and analytical techniques
  • Review of Over the Prescribed Limit (OPL) cases, Alcohol technical defence and assessment of pre and post accident drinking.
  • We can carry out identifications and comparison of a wide range of materials using a range of microscopical and analytical techniques