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 investigating Zou's offences initially questioned whether the two women might be the same person, because the two attacks sounded identical and happened in such a short space of time.
This timing showed Zou was confident, a source familiar with the investigation told the BBC World Service. He was getting away with it, so he wanted to do it more and more, they said.
Warning: This story contains descriptions of sexual violence
Zou was sentenced to life in prison, with a minimum term of 24 years, in June.
The Chinese national was convicted for drugging and raping 10 women - three in the UK and seven in China - between September 2019 and May 2023. All victims appear to have been Chinese.
Detectives - who described Zou as one of the UK's most prolific predators - expressed fears that he may have attacked 50 more women.
Since Zou's trial, 24 women have come forward in both the UK and China, including the victims of these two attacks.
The first woman, referred to as Rachel, met Zou for drinks in late October 2022. She was given a cocktail that left her dizzy and unable to resist as he assaulted her.
Despite reaching for help, Zou intervened and took her phone, creating a barrier to her freedom. The friend she sought help from could not reach her due to Zou's manipulation.
Finally dropped off at home, Rachel later regretted not reporting the crime, believing it could have prevented another victim's ordeal.
The second victim, referred to as Female D, was attacked shortly after Rachel. They both reported their experiences to the police in 2025, after learning of Zou's conviction, leading to a renewed investigation.
Concerns about Zou's methods, including online searches for sleeping drugs and the assembly of spy cameras, illustrate the premeditation of his crimes. Despite his conviction, investigations into his potential victims continue, highlighting the ongoing threat posed by offenders like him.