Afterwords: Forensics: Evidence, Ethics & Evaluation

Isaac Parham · Wed, 15 Dec 2021

Cold cases, biometrics and ethical quandaries – what we learned from our Forensics collection.

forensics investigator

The proliferation of True Crime in recent years has made forensic experts of us all. But beyond the entertainment of shows like Making a Murderer, how much do we really understand about the realities and possibilities of forensics? That was the question our recent collection (Forensics: Evidence, Ethics & Evaluation) set out to answer. And answer it we most certainly did...

Through our academic experts, we took viewers behind the yellow tape and deep into this fascinating world. Here’s a rundown of our favourite moments, along with what we learned and related things to watch, read and listen to.


“The law is catching up with the technology”

Professor Richard Guest – a computer scientist by vocation – began his Garden Talk with a short history of biometrics, explaining that they have in fact been used for law enforcement purposes for decades if not centuries. From fingerprints right through to facial recognition. 

What he was more concerned with, though, was the ethical implications of these technologies, particularly given the police now rely on biometrics from external sources. A picture on a suspect’s smartphone, for example.

He framed the challenge in these terms: firstly, we’ve got to ascertain how reliable the data is and that it’s used responsibly; secondly, we’ve got to account for the fact that devices can be hacked and manipulated; and thirdly, we must find ways to overcome the implicit racial, gender and age-based biases of the algorithms.

This was an illuminating talk that gave us deeper insight into the uses and possibilities of biometrics. It also made us think more widely about the runaway train of technology and whether ethics can ever truly catch up.

Lightbulb Moment

Biometric samples are a protected characteristic alongside gender, ethnicity and religion. Because it is you.”

Watch back: Is it ethical to use biometrics to catch criminals


“There’s something honourable about reintegrating somebody and giving them a second opportunity at life”

As a Consultant Forensic Psychiatrist and expert witness, Dr Sohom Das has spent his career assessing and rehabilitating defendants with mental health conditions. He joined us to deliver a powerful Garden Talk on the nature (and challenges) of his work and explore the intersection of mental health and criminality. 

He did so by relaying the case (and his work within it) of Yasmin, who aged eighteen had suffocated her younger cousin to death. In the wake of this tragic crime, Sohom was tasked with conducting a clinical assessment of Yasmin’s mental state. He outlined the complexity of this process:

 “When I saw her she was passively aggressive. Although superficially polite, she wasn’t really answering my questions, she wasn’t engaging in conversation. She would say ‘I can’t remember’ to my questions, or ‘I don’t know why that’s relevant’."

The rest of Dr Sohom’s Talk took us through the assessment process and the factors that influenced his subsequent recommendation to the judge. The story was a gripping one and testament to the importance of experts like Sohom, who dedicate their careers to ensuring justice is meted out even-handedly and with the mental health of suspects taken into account. 

Lightbulb Moment

“True psychotic voices tend to be external, so you hear them outside your head.” 

Watch back: How do we handle mentally ill offenders?


“We have to be unbiased to both parties and speak only to the evidence”

“The discussion of sexual assault - rape, molestation - are all difficult conversations,” said Dr Candice Bridge early on in her Garden Talk. And though her Garden Talk did veer into difficult territory at times, it was never anything but vital and compelling. 

The opening saw Candice take us through the damning statistics (“only 9% of rapists are actually charged”) and the forensic techniques employed to try and overcome these low conviction rates. She explained how DNA is only one part of the puzzle: investigators also look for transference of hair, lubricants, and even glitter. In one fascinating passage, Candice told us how her work had made it easier for forensic teams to identify certain lubricants and link them to suspects.

“I first thought, let me see how I can develop a method for identifying lubricants; create characteristics of various types of lubricants based on their chemical composition. 

“And then I wanted to create a database that allows me to populate all of the chemical information to give it out to the community... if I have that information for all of these lubricants then the crime labs can look through my database and say, ‘you know what, this lubricant collected off of this victim is, or is very similar to, something off this database.’”

Candice’s Talk was a lesson in balance. She brought us into the science of her work but never lost sight of the emotive nature of the cases. She gave us detail but always brought it back to the problems she has spent her career trying to solve. 

Lightbulb Moment

“DNA says who was there. It does not say who did what.”

Watch back: How can investigators identify a criminal when they don’t leave DNA?


“There was no simple solution here that was going to crack this case”

Only 5% of murder cases unresolved after one year end in an arrest. So forensic experts like Professor Jim Fraser, who specialises in investigating cold cases, face an uphill battle. He joined us in The Garden to share more about his work and unravel the mysterious case of Gareth Williams, a Welsh mathematician working for MI6 who was found dead at his home in 2010. 

Jim explained that he was brought in to investigate the death of Gareth Williams eighteen months after it had occurred. What he discovered was a highly unusual case complicated by competing investigations (“there was a murder investigation team and there a counter-terrorist team, because of the links to MI6”), press intrusion and missing evidence. Then there was the enigma of Gareth himself – a brilliant mathematician who had achieved a first class degree aged just seventeen. 

After setting up the dynamics of this knotty case, Jim engrossed us in the rigorous process he had used to untangle it. From reviewing shoe marks discovered at the scene to scoping out the bondage websites Gareth Williams had been visiting. 

Beyond the fascinating details of the case itself, Jim’s Talk gave us a deep insight into what it takes to become a forensic expert. To step into the heat of a high-profile case in which everyone has a theory and separate the facts from the conjecture. As for what really did happen to Gareth Williams, Jim admitted that he couldn’t be certain. But based on the evidence available to him at the time, he was certain the right judgement had been made.

Lightbulb Moment

“As far as the media was concerned, Gareth Williams was a spy straight out of a John Le Carre novel. These were stories they just couldn’t resist. They treated Gareth Williams as a caricature – and he wasn’t a caricature.”

Watch back: How do you separate fact from fantasy in a cold case?


Explore more

We hope you enjoyed this collection of Garden Talks. To help you explore more on this theme, we’ve prepared a list of related things to watch, read and listen to. Tag us on Twitter, Instagram or Facebook (@thegarden_talks) to share your own reflections and continue the conversation. 

Read: Murder Under the Microscope: Serial Killers, Cold Cases and Life as a Forensic Investigator (Jim Fraser)

Read: Forensic Science: A Very Short Introduction (Jim Fraser)

Read: DNA Phenotyping: The Future of Forensics (Medium)

Watch: Forensics: The Real CSI (BBC)

Watch: A Psych for Sore Minds (Dr Sohom Das, YouTube)

Watch: Making a Murderer (Netflix)

Listen: Serial Podcast (Apple Podcasts)

Forensics: Evidence, Ethics & Evaluation

This collection looks at crime, from how to solve a criminal investigation with evidence to how we treat offenders with mental health problems, and gives us intriguing insights into the myths and reality of forensic science.

Is it ethical to use biometrics to catch criminals?

Dr. Richard Guest

Fingerprints are getting rarer - everyone's seen the TV shows. What new tools can we bring in to confirm a criminal's identity, and is it ethical to use them?

How do we handle mentally ill offenders?

Dr Sohom Das

It's not always clear what drives a criminal to act the way they do. How does the justice system deal with offenders whose behaviour is rooted in mental illness?

How can investigators identify a criminal when they don't leave DNA?

Dr. Candice Bridge

DNA is the go-to forensic evidence in many criminal cases. What other trace evidence can be used to identify the perpetrator when they don't leave DNA behind?

How do you separate fact from fantasy in a cold case?

Professor Jim Fraser

Cold case reviews often have to battle misinformation and conspiracy theories, as well as missing pieces. How do investigators see through the chaos to a solution?