A series of attempted burglaries has happened. Three neighbours noticed damage to and around their houses, foot prints were found in every garden and two t-shirts plus some pieces of glass with stains were recovered. Tools and shoes were confiscated later from suspects.
Yesterday it was time for three hours of seminars. For once not for me to attend, but to teach as part of Lisa’s Forensic Science and Criminal Justice module. The theme of the seminars was Hand-on Techniques, so I had created three working stations; one with tool marks, one with foot casts and one with blood spot evidence (presumptive).
The tool mark station contained three pieces of wood; one from the fence of the first neighbour, one from a shelter in the backyard of another neighbour and one from just below the window of the last neighbour. The question was to see if the casts made from the marks could be matched to the confiscated tools and to investigate if the marks from different pieces of wood could be linked to the same tool. After puzzling for a while, some students were very happy to create more misleading marks for the next groups.
At the foot cast station, the students had to see if they could find a match between confiscated shoes and three casts being made in the gardens of the neighbours. This seemed like an easy puzzle to everyone as all confiscated shoes that had very different patterns, however only 2 out of the 9 groups were able to match the ‘right’ shoe to the right cast without any help from me or Annelies (who was also helping Lisa out with the seminar series). They also investigated wear and tear marks to exclude other similar shoes being produced together with the confiscated shoe.
The station with ‘blood’ spot evidence was set up with the Kastle-Meyer test; a presumptive test to get an indication if stains are blood or just other stains. If a purple colour appeared after adding hydrogen peroxide to the swabs used to swab the stains, the stain is presumed to be blood. Some stains on the t-shirts didn’t give a colour change, but all spots on the pieces of glass did.
It were fun seminars, whereby many questions arised about what can be encountered in real investigations and what’s fiction. And let that be the topic of the next seminar I’ll be giving in two weeks. To be continued:)
*All students depicted in the photos gave permission for the photos and for use in this blog.
I think you love giving such seminars. Maybe you can also
write a book about criminal investigation.
When you have finished your study of course.
Succes with your next seminar.
x Elly Valkenburg.