BEIJING - Although a high-profile corruption case involving former Chongqing Beibei district Communist Party secretary Lei Zhengfu ended last month when he was sentenced to 13 years in prison, revealing photos posted online of Lei and a young woman engaged in sexual activity are still a hot topic in China.
He is not the only high-level official toppled after an inappropriate relationship was investigated by the disciplinary authorities.
Earlier this year, Yi Junqing, former head of the party's central compilation and translation bureau, was removed from his post - also on charges of pursuing an "improper lifestyle".
A woman claiming to have been his mistress had posted a detailed description of the alleged affair on the Internet. The post quickly went viral.
These so-called improper lifestyles are, in fact, a form of sexual bribery, a phenomenon that's increasingly common. However, they are hard to identify because of an anomaly in Chinese law, according to Dr Yang Xiaojun, a legal expert at the Chinese Academy of Governance.
Under Chinese criminal law, there is no accurate definition of sexual bribery, let alone any means of identifying or punishing it, Dr Yang said.
"Therefore, the definition of corruption should be widened to include this as soon as possible," he said, adding that he has been calling for the law to be revised for a number of years.
According to the law, the charge of bribery is concerned purely with financial reward. That means officials found to have accepted bribes of a sexual nature are dealt with by a disciplinary committee and not a criminal court.
Mr Yi Shenghua, a Beijing-based lawyer who has specialised in corruption cases for 10 years, said: "It's hard to identify, or obtain evidence of, sexual bribery."
He said that a major challenge is to distinguish between a purely sexual transaction and an illicit affair based on genuine affection.
He said: "Sometimes, a person's actions can be criticised only from a moral standpoint and will not result in serious punishment."