The award-winning Chinese documentary photographer Lu Guang has gone missing. The photojournalist won three World Press Photo Awards for candidly depicting the dark side of China’s booming economy, including images of environmental pollution, drug addiction, and AIDS.

In a case that’s eerily reminiscent of the 2011 abduction of Ai Weiwei, Lu disappeared a month ago after traveling to Xinjiang to meet other photographers and document the region which is home to a large Muslim population being held in internment camps. Citing the United Nations estimates, the South China Morning Post reported that authorities have detained more than one million Uyghers and other Muslim minorities in the extrajudicial camps.

Lu’s wife, Xu Xiaoli, says she last heard from her husband on November 3 and later learned he had been detained by state security officials during his trip to Xinjiang. It remains unclear why the photographer was arrested. Lu is a permanent resident of the US and lives in New York with his wife and children.

In statement responding to his disappearance, Hong Kong’s Foreign Correspondents’ Club urged Chinese authorities to acknowledge his detention and said it was “deeply concerned” over his arrest. The club called on the government “at the very least, confirm Mr. Lu’s whereabouts, and ensure that he is safe, and, if he has not broken any laws, be allowed to leave China and return to his family in the United States as soon as possible.”

Chinese policemen push Uyghur women. Photo by Guang Niu/Getty Images.

Reports of Lu’s detention has sent shockwaves through the Chinese community of photojournalists. Fellow photographer He Yanguang told the South China Morning Post that his missing colleague knew that his investigative photography might provoke the authorities. The artist’s work has in the past documented the “AIDS villages” in remote areas of Henan province as well as severe industrial pollution effecting China’s rivers, farmland, and air.

“He knows clearly the significance of his work to society,” He said. “I hope Lu can return home safe soon.”