Two women who reported being drugged and raped by prolific sex offender Zhenhao Zou said they were attacked within 24 hours of each other, the BBC has established.

The first woman who says she was raped told us she was shocked to learn about the second attack and had since felt guilt for not reporting her rape sooner.

Metropolitan Police detectives initially questioned whether the two women might be the same person, as the attacks sounded identical and happened in such a short time frame.

This timing indicated Zou was confident, a source familiar with the investigation told the BBC World Service, stating, He was getting away with it, so he wanted to do it more and more.

Zou was sentenced to life in prison, with a minimum term of 24 years, in June of this year. The Chinese national was convicted for drugging and raping 10 women between September 2019 and May 2023, with all victims believed to be Chinese.

However, following his trial, detectives expressed concerns he might have attacked up to 50 more women.

Since then, 24 women have come forward, including the two victims referenced in this case.

The first woman, reportedly named Rachel, met Zou for drinks in late October 2022. After he provided her with a cocktail that left her incapacitated, she says he raped her.

Rachel attempted to call a friend for help, but Zou took her phone and spoke to the friend himself.

He did not return Rachel's phone until the next day. In frantic WeChat messages, Rachel expressed her distress, indicating she was still with Zou. Her friend had tried to intervene but was met with Zou's evasiveness about his location.

Rachel refrained from reporting the incident due to her fears of insufficient evidence and potential public exposure.

Evidence from a police raid on Zou's apartment revealed the presence of butanediol, a substance that converts to the date-rape drug GHB in the body. While it’s controlled in the UK, it can be easily obtained in China.

The case took another turn when a second victim, referred to as Female D, revealed she had also been assaulted by Zou on the same night as Rachel, shortly after she'd been dropped home.

Both women subsequently reported their experiences to the appropriate authorities, shedding light on Zou's heinous crimes and the urgent need for greater awareness surrounding sexual violence.