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Forensics

We’ve all seen the glamorous forensic scientists on TV solving case after case thanks to the incredible ability of forensic science. In Episode 10 of Ever Wondered?  Series 2, Dr John Watt shows us some of the cutting-edge forensic science research that’s happening in New Zealand.

Investigating back spatter

John meets one of New Zealand’s most renowned forensic experts – Dr Michael Taylor from ESR (Environmental Science and Research). Michael explains to John that forensic science is the application of scientific methods to criminal investigation. He outlines his interest in back spatter analysis and how he’s working on understanding exactly what happens when someone is shot in the head.

John goes to a firing range to visit Nardia Foote, a University of Auckland master’s student working on this project with Michael. He sees how she sets up an experiment to find out what happens when a head is shot with different calibre guns. These guns fire different calibre bullets through a simple gelatine-based model of the human head. A high-speed camera captures images of the bullets as they hit and travel through the model head.

The next step in solving this forensic puzzle is using the information provided by the high-speed camera to create computer models. This work is done by Dr Peter Davidson at the University of Otago. Peter analyses the data to understand the mechanical principles involved in back spatter. John visits him to see how the computer models are created and just what conclusions they can provide.

Watch Episode 10, Part 1

Developing new forensic tools

John meets two Auckland University postgraduate students, Ashleigh Fox and Eletra Williams. Their research projects have the potential to lead to new methodologies for forensic science.

Ashleigh explains to John that her research focuses on fingerprints and the reagents used to enhance them at a crime scene. John lends a hand by offering some of his own blood so that Ashleigh can show him an experiment looking at fingerprints made by blood. Ashleigh wants to find out if any of the reagents used to enhance bloody fingerprints can interfere with extracting DNA or RNA from the same fingerprint. Her research has the potential to change the way crime scenes are processed in the future.

Fellow student Eletra Williams is interested in developing a new technique for establishing the post mortem interval when a body is found outside. She is using fingernail and toenail samples, as nails are quite resistant to decay because they have a strong biochemical structure that could potentially protect the DNA and RNA in the cell. Eletra is extracting and amplifying the RNA from nails exposed to the outdoors and looking for signs of degradation. If she can determine how long it takes for RNA to degrade when a nail is exposed to the elements, this may help determine how long a body has been in that location.

Watch Episode 10, Part 2

Marine bacteria involved in decomposition

John travels to Dunedin to find out about a unique forensic project. He meets PhD student Gemma Dickson who is looking at marine bacteria associated with decomposition. Her research aims to find a better way of calculating the time of death or time of submersion for bodies found in coastal marine environments. John tags along with Gemma on a field trip to the picturesque Otago coastline to find out what role submerged pigs’ heads play in her work. Through her research, Gemma has made some world-first discoveries, including discovering new bacteria species.

Watch Episode 10, Part 3

Activity idea

In conjunction with this episode of Ever Wondered?, your students may enjoy this activity.

Towards the end of part 3, we hear that one of the next steps for Gemma is to see what effect clothing would have on the decomposition process. You may like to adapt this student activity to find out how biodegradable different items of clothing are.
Biodegradability experiment

Context link

Find out more about how the latest DNA technology is used to help solve crimes in New Zealand in this Biotech Learning Hub focus story.
www.biotechlearn.org.nz/focus_stories/forensics external link

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