Stills of the second season of documentary series The Guardians of Jiefangxi, which shows policeman Zhang Peng and his colleagues from Pozijie police station patrolling the streets. CHINA DAILY

Moreover, they added many elements in the postproduction to make it lively, including online buzzwords, amusing sound effects and background music.

"Many cases we witnessed in the police station are not about extremely evil things. Instead, they tend to show shortcomings in human nature, such as a suspect's absurd explanations. We sometimes ridicule such shortcomings in postproduction to emphasize the amusement, since we want to tell people that, although such things seem funny, they may break the law," says Xiao.

"In this way, we try to spread more knowledge about the law, enhance people's memory, and reflect the police officers' professionalism in law enforcement. I believe it is an advanced, effective way of expressing this, much better than a boring lecture," she adds.

Compared with the first season, the second shows the work of more types of police officer, such as traffic police and special police, and more criminal cases, such as the apprehension of drug dealers. The second season, which concluded on Jan 1, also focuses on the cultivation of new police officers.

In the documentary series, many social issues are elaborated upon, including drunken driving, domestic disputes and juvenile delinquency.

Xiao cites an example in the fifth episode in which a drunken man fell down some stairs and suffered a serious head injury. Several people passed him by without offering aid. By the time the police were called, he had passed away.

"This case aroused enthusiastic discussion online, about what a passerby should do. Some people say they don't want to help the man for fear of being scammed, while others say even if they don't want to help him, they would have called the police," says Xiao.

"I hope such discussions can make people realize that a benevolent action may make a difference, or even totally change a person," she adds.

Zhang and some other police officers went to universities in Changsha to lecture on the dangers of telemarketing scams.

He hails the documentary for helping him fulfill his mission. "With the online popularity, people are more convinced when we try to pass on law-related knowledge to them," says Zhang.

His colleague, police officer Huang Junlong, who is also head of the Pozijie police station, says: "When our officers become online celebrities, they find themselves under greater scrutiny by the general public, which also urges them to attain a higher standard in their work. This is pressure, but also motivation."

Contact the writer at wangru1@chinadaily.com.cn