Ms. Riddle is an operational psychologist currently on staff with the Australian Public Service.  She provides psychological consultation on threat assessment in counterterrorism, communicated threat, stalking, workplace violence, and family violence cases, including cases involving mental disordered offenders. Ms. Riddle also provides training to law enforcement and mental health services on the identification, assessment, and management of stalking and fixated behaviour.

She has previous published articles in Psychiatry, Psychology and Law, and the Australian and New Zealand Journal of Evidence Based Policing.

Ms. Riddle is a current PhD candidate at ANU's POLIS: The Centre for Social Policy and Research. Her research focuses on young people's involvement in violent extremism.