Public security officials in the city of Wenzhou quickly removed the notice on Wednesday after its discovery by Internet users had created a sensation on Chinese social media.
The deleted page, which is still viewable in Google's cache, showed the Wenzhou Economic and Technological Development Zone's public security bureau awarding two contracts to Wuhan Hongxin Telecommunication Technologies Co, a subsidiary of a major information technology company affiliated with China's central government.
Chinese government agencies routinely disclose procurement contracts on their web sites in a nod toward transparency, but the Wenzhou police probably did not intend to share with the world the descriptions of their purchases.
Another product, a Trojan Horse virus itself, bought for 100,000 CNY ($16,096), "allows users to monitor phone conversations, text messages and photos in real time".
Wuhan Hongxin's publicly listed telephone line appeared to be disconnected on Wednesday, and could not be reached.
An employee of the Wenzhou police agency involved in the purchase referred Reuters to the agency's spokesman, whose telephone also appeared to have been disconnected.
The revelations threaten to tarnish the reputation of Wenzhou, which China has promoted as a model for a "smart city" that boasts interconnected telecoms systems and cloud computing capabilities.
Many users of Weibo, China's microblogging network, slammed the police and software company.
"Is it right for the police to be doing mobile spying in such a high-profile way?" said one Weibo user, Yang Haifeng. "How impressive that Wuhan Hongxin has these products!"
China has long been accused by countries such as the United States of carrying out extensive hacking. The government in Beijing has bristled at the accusations, saying it is resolutely opposed to all forms of hacking and is often a victim itself.
© Thomson Reuters 2015