The chief of the Taiyuan public security bureau, Liu Suiji, was detained last night, just hours after the Central Commission for Discipline Inspection (CCDI) announced investigations into two other top Shanxi officials.
Liu is the third Taiyuan public security bureau chief in two years to be caught in a widening crackdown on graft in the coal-rich province.
Liu was promoted to his position in late 2012 after his predecessor, Li Yali, was put under investigation.
"Liu was promoted by Chen Chuanping, his fellow-townsman and previous boss," said Li Jianjun, a former Shanxi journalist who had publicly accused Liu of corruption. "Chen insisted on the promotion even though the provincial-level public security bureau didn't agree."
Earlier yesterday, the CCDI announced that Chen, a member of the Shanxi provincial party committee and secretary of the Taiyuan municipal committee, and Nie Chunyu, secretary of the provincial party committee, had been detained.
Only two months ago, Ling Zhengce , elder brother of ex-president Hu Jintao's key aide Ling Jihua , was detained for suspected corruption. It remains unclear whether the latest detentions are related to Ling's case.
Chen presided over a televised conference on combating corruption on Friday, Taiyuan Daily said.
The announcement of an investigation into two senior officials from the same provincial party committee on the same day is a rare occurrence.
In the past six months, Shanxi has seen five provincial leaders fall from grace. Four were from the provincial party committee: Chen, vice-governor Du Shanxue , Luliang mayor Ding Xuefeng and provincial standing committee vice-chairman Jin Daoming .
The investigation is part of the anti-graft campaign launched by President Xi Jinping and CCDI chief Wang Qishan in November 2012. The campaign has engulfed ex-security tsar Zhou Yongkang, who was placed under official investigation last month, and former Central Military Commission vice-chairman Xu Caihou in June.
Shanxi has been under pressure to combat corruption since it was criticised by a government inspection team in February.