蜜芽传媒

"I hate you," a woman says. "It's pointless," a man replies. "The sound insulation here is very good." Grainy camera footage reveals that, behind closed doors, a hidden sex offender, masquerading as a respectable PhD student, thrived.

Police uncover a series of shocking drug-assisted rapes, perpetrated against unconscious women, filmed secretly by "one of the most prolific sexual predators" UK police have ever seen.

Why did a seemingly intelligent and gifted academic carry out crimes against women he rendered defenceless and how did his attacks go undetected?

A journalist, a forensic psychiatrist and a former police detective hear from the victims whose bravery brought the truth to light. They delve into the disturbing psychology that drove Zhenhao Zou to commit his sex crimes and examine evidence, described by prosecutors as a 鈥榬ape kit,鈥� secreted throughout a luxury London flat.

If you have been a victim of sexual violence details of help and support are available at bbc.co.uk/actionline.