A Nanjing real state agent has created a database cataloging local residences where suicides, murders and unnatural deaths took place, Nanjing Morning News reported on Wednesday.

Such houses are regarded as "haunted".

The database was launched to avoid purchase disputes, said Shu Lili, a marketing department manager at Lianjia Property Agency.

Under the General Principles of Civil Law, "civil activities should respect social ethics"; buyers have rights to cancel property purchase contracts through the courts if agencies fail to disclose the "dark histories" of houses, an unnamed lawyer told Nanjing Morning News.

From March 2013, the agency began collecting data on haunted houses through media reports and from local residents. About 200 haunted properties have been placed on the list.

The agency promises to buy back any residences it sold if th buyers were later to learn an undisclosed unnatural death had occurred in their home.

Investors look for haunted houses because they can buy them at sharply reduced prices, Shu said.

In 2011, an investor bought an Nanjing apartment said to be haunted for 50 percent less than market price.

Dwellings where violent deaths have occurred can generally be sold at 20 percent discounts, Shu said.