An illegally-registered fake "hukou" of the "house sister," a woman found to have illegally amassed 20 homes using multiple identities, was revoked by Beijing police on Thursday.

Police also launched an investigation into the case, according to sources with the Beijing Municipal Public Security Bureau.

It was confirmed that Gong Aiai, former deputy head of a bank in Shenmu County in northwest China's Shaanxi Province, had four hukou, including a legitimate one and a Beijing-registered fake one.

The police who were responsible for Gong's hukou registration in Beijing have been suspended from duty. Gong's houses, cars and other properties in Beijing have been seized by the police.

The hukou is a Chinese permanent residence registration and personal identification system governed by public security departments. In China, one individual has one legitimate identity and hukou record.

Gong had been allowed to acquire more than 20 houses worth a total of about 1 billion yuan (159 million U.S. dollars) with her multiple fake hukou. China's property market controls restrict individuals buying multiple homes, but "ghost" identities can help householders skirt the restrictions.

On Thursday, Beijing police also said they are checking and investigating another Hukou forgery scandal involving a disciplinary official from north China's Shanxi Province.

Zhang Yan, a staff member with the disciplinary commission in the city of Yuncheng, was exposed by online posts to have two hukou, registered in Beijing and Shanxi respectively.