Meng Guanggang looks the part of a private detective with his trench coat and dark glasses, but the crime-solving expertise he and his collegues bring to cases is most important. Photo provided to China Daily

You've screwed up if people can tell you are a private detective. We try to be the most inconspicuous people in a crowd. Sometimes, we pretend to be delivery men or cleaners to gather intelligence." Wang Tong, private investigator.

Meng Guanggang recalls having his car set on fire and being chased by gangsters.

He doesn't take cases involving organized crime anymore. "You realize safety's value after you lose someone you care about," he says.

The 65-year-old's outlook changed after his son died of disease years ago and his wife passed away in 2008. "I made rules against dealing with extremely dangerous cases, especially involving the mob, to protect my family and private investigators," he explains. "We don't take them－no matter what they pay."

China's "Sherlock Holmes" earned his moniker by opening the country's first private detective agency in Liaoning province's capital Shenyang in 1993. Its team of 10 has become China's largest with more than 50 full-time and about 100 part-time investigators. There are more than 1,000 agencies employing 200,000 nationwide, experts say. There are no official statistics.