Amid a rolling purge of officials and generals accused of corruption, the Chinese authorities have detained two investigative journalists — for writing about corruption.

China’s leader, Xi Jinping, warned after taking power in 2012 that graft would spell “the end of the party and the end of the state” if left unchecked. He has since presided over a yearslong drive to root out what he sees as wayward officials and military officers.

But the targets of that effort, which escalated dramatically last month with the purge of a general second only to Mr. Xi in the military command, have all been chosen by the ruling Communist Party, which allows scant space for independent investigations by journalists or others.

In a sign that the party is determined to keep its monopoly on the policing of corrupt officials, a prominent investigative journalist, Liu Hu, and a colleague, Wu Yingjiao, were detained this week after posting an account of official corruption in the southwestern province of Sichuan.

Police in Chengdu, the capital of Sichuan, said in a statement that a 50-year-old man surnamed Liu and a 34-year old man surnamed Wu had been detained on suspicion of “making false accusations” and conducting “illegal business operations.”

Mr. Liu’s lawyer, Zhou Ze, confirmed the identities of the two detained men on the messaging app WeChat. He wrote that he had visited Mr. Liu on Wednesday at a Chengdu detention center, adding that the case against his client appeared to be based solely on the article he coauthored with Mr. Wu.