Introduction to some basic biology

We’re going to start with some basic biology and how we can use this in criminal investigation. Keep in mind the information you already know about the Case Study as we look at the materials and in particular what aspects of biological evidence may be important.

The video opens by illustrating how forensic biology can answer some of the questions contained in the 6Ws tool.

Note the variation on the presentation of the 6Ws, by using a device called the “Investigative Star” which shows how each of the Ws can link to any and all of the others, emphasising that the tool is shorthand for an iterative process. There is then a brief review of the biochemistry of blood – many of you will be familiar with this, but those who are not should make sure that they understand the basics and the terminology used.

Probably the most important part of this section is that describing how blood stains are examined at the scene and in the laboratory, with the sequence of visual inspection -> presumptive or screening test -> confirmatory test. To see how these can be condensed into one test, view the video on HemaTrace in the ‘see also’ resource section below.

Finally, there is a very brief overview of other body fluids, mainly semen.