The official Thanh Nien newspaper said Hoang Khuong, 37, whose real name is Nguyen Van Khuong and who writes for the Tuoi Tre newspaper, was detained on Monday.
He will be held for four months while authorities investigate his case.
Thanh Nien said Khuong had posed as the relative of a man whose motorbike had been confiscated for an illegal street race and had bribed former officer Huynh Minh Duc with 15 million dong (U.S. $710) to have it returned.
Duc was arrested on Nov. 18 last year for taking bribes from a traffic violator after Khuong wrote about it in articles published in July.
Khuong’s lawyer, Phan Trung Hoai, said he was unable to comment on the charges against his client because he had just taken on the case.
But Pham Quang Nghiem, another lawyer familiar with the case, told RFA that he believes Khuong was unjustly charged.
“I was shocked to know that reporter Hoang Khuong was arrested because I appreciated his work and articles about police corruption in 2011. I think his articles reflect his hard work—the way he collected evidence was convincing,” he said.
Tuoi Tre had quoted Khuong as saying he made an error in his attempt to gather evidence for a series of stories about police corruption. He did not say in his article that he provided the bribe.
The series touched off a public backlash against graft in Vietnam.
Paris-based journalism watchdog Reporters Without Borders was quick to condemn Vietnamese authorities for arresting Khuong.
“Khuong should not be charged with bribery because of what he did in the course of an undercover investigation,” Reporters Without Borders said Tuesday.
“He was acting as a reporter, not for personal gain. He is a well-known journalist who has written many stories about police corruption. The authorities should free him at once and abandon any thought of prosecuting him in connection with what he exposed. On the contrary, they should take the appropriate action in response to his investigative reporting, which was in the public interest.”
Reported by RFA’s Vietnamese service. Translated by Viet Ha. Written in English by Joshua Lipes.