The words ‘known’, ‘exemplar’, ‘specimen’ are essentially equivalent and used to describe materials or samples of ‘proven’ provenance or origin. There are many things that can be determined from questioned material on its own but questions relating to any source attribution require samples of a ‘proven’ nature, (i.e., known, specimen, or exemplar material) for comparison purposes. 

Specimen samples must be obtained by the client in most situations.  Along with the questioned sample they would then be provided to the examiner. 

Obtaining appropriate and adequate specimen samples is critical to an effective examination.  Please contact the examiner to discuss the collection and submission of such material PRIOR to obtaining them. 

There are two main types of specimen samples that may be considered:  ‘collected’ and ‘request’.  Pros and cons of each are discussed below:

Collected samples are exemplars produced in the course of routine day-to-day activities by the suspect individual or device. 

The first advantage of collected samples is they are representative of the normal, routine behaviour of the individual/device and are not (likely) to be disguised or distorted in some way.  This refers to any sample that was produced in the course of daily business or routine, without consideration for later examination.  Another advantage is that such samples may be historical in nature (i.e,, having been produced on some date in the past) and representative of the behaviour at that time (e.g., handwriting or signature samples for a deceased person).  Yet another advantage is the potential to locate exemplars under specific conditions or circumstances that cannot be replicated at the present time.   On the ‘negative’ side of things, collected samples may not be completely comparable to the questioned samples in terms of the precise conditions or content of the material in question.  While the samples may represent the individual/device’s ‘habitual’ behaviour at the time of production, the samples will not help if the questioned material is of a different type, nature, or content.  The biggest ‘negative’ for collected samples is proof of source.  It is important that some ‘proof’ of the source of the sample be possible.  This can be achieved in many ways but it something the client needs to consider; it cannot be done by the examiner.

Request samples  are those produced at the request of the investigator (or client) for the express purpose of being examined.  The key advantage of these samples is that they can be customized to provide comparability to the questioned samples in terms of content, nature, and (sometimes) conditions.  As such, request samples often provide the best direct comparability to questioned samples.  Proof of source is also a non-issue as it can be given by the person obtaining the samples.  On the ‘negative’ side of things, request samples may not be available — either because the individual refuses to provide any, or they are not able to do so (i.e., a person has passed away or the device is not longer in-service).  In addition, samples that are not contemporaneous may not display the same features/habits simply due to changes over time.  Finally, request samples may not be able to replicate every aspect of the original conditions. 

Ultimately, collected and request samples are complimentary to one another.  So an ideal submission will have both types. 

One last note:  in some situations it may be possible to have the examiner obtain the specimen ‘request’ samples from a suspect.  Doing so generally requires a ‘remote’ visit.  If this is desired, please discuss the matter beforehand with the examiner. 

Related FAQs:

  • What purpose do specimen samples serve?
  • What type of specimen samples do you need?
  • How much specimen material do you need?
  • How is proof of specimen material achieved?