The backpacker killer. The Claremont killer. Ted Bundy. The crimes serial killers commit linger in our memories for decades.

But when was the last time you heard about an active serial killer in the news?

In our final episode of Criminal Psychology, we probe the lead-crime hypothesis, find out about 'chemical castration' and ask — where have all the serial killers gone?

And a heads up that this episode explores some heavy themes including sexual assault, child abuse, suicide and murder. It also contains the names of Aboriginal people who have died. Please take care while listening.

If you've got more questions for our forensic psychiatrist Dr Rajan Darjee, please send them to us! We're going to make a special mail-bag episode featuring your burning true crime questions. Get in touch by emailing us at mind_rn@abc.net.au with the subject line "criminal psychology question".

Guests:

Dr Rajan DarjeeForensic psychiatristClinical Director, Forensic Behavioural Assessment and Consultation Services

Dr Xanthe MallettCriminologistAssociate Professor of Criminology, Central Queensland UniversityCo-Director, Queensland Centre for Domestic and Family Violence ResearchPodcast co-host, Motive and Method

Credits:

Presenter/producer: Sana Qadar
Senior producer: James Bullen
Producer: Rose Kerr
Sound engineer: Emrys Cronin

More information:

The lead-crime hypothesis: A meta-analysis

Support resources:

Where have all the serial killers gone?

All In The Mind