The deputy head of the mainland's top economic planning agency has officially been placed under investigation by the Communist Party's top graft-busting organ on suspicion of "serious discipline violations". A one-line Xinhua dispatch yesterday quoted unnamed officials within the Central Commission for Discipline Inspection (CCDI) as saying that Liu Tienan, the 58-year-old deputy director of the powerful National Development and Reform Commission (NDRC), was being investigated, but it gave no details. Sources close to the matter said Liu was formally placed under investigation yesterday and that his home and office were searched by CCDI officials on Saturday night. Liu is the latest senior official caught in a renewed anti-graft campaign launched late last year by Beijing's new leaders. President Xi Jinping has warned that corruption could lead to the demise of the party and vowed that his anti-graft initiative would catch both low-ranking "flies" and higher-up "big tigers". The only other vice-ministerial-level official thus far brought down by the anti-graft campaign was Li Chuncheng, a deputy party secretary of Sichuan who was sacked and placed under investigation in early December on suspicion of severe violations of discipline - a common euphemism for corruption. Liu's case was first announced on December 6 on the microblog account of a deputy editor of news magazine Caijing . Luo Changping reported on his verified Sina Weibo account a series of allegations against Liu, including that he fabricated academic credentials, improperly profited from his position and kept a mistress. On the same day, Liu, who until March was also head of the National Energy Administration (NEA), attended the 9th China-Russia energy talks in Moscow along with newly appointed anti-corruption tsar Wang Qishan, then a vice-premier. The NEA wasted no time in labelling Luo's allegations "slander and rumour", with an unnamed spokesperson telling The Beijing News : "We're contacting the relevant cybermanagement authorities and reporting the groundless accusation to police. We'll deal with the case through legal means." Liu made several public appearances in the following couple of weeks, including at a national working conference on development and reform on December 18. However, a source familiar with the case told the Post that Liu had been barred since mid-December from attending official activities related to external affairs. "Liu is the latest high-ranking official brought down by the mistress he kept," the source said, adding that the mistress became frustrated after they broke up and started to seek help, while divulging information about Liu after he allegedly threatened to kill her. "They got to know each other in Japan, and the mistress was the ghost writer [of] Liu's academic thesis when he was studying there," the source said. According to Liu's official profile, he was an economic attaché at the Chinese embassy in Japan between 1996 and 1999. Xinhua also released a short commentary yesterday branding Liu a "moth" who had nowhere to hide and praising Luo's whistle-blowing efforts, saying they sent "a positive message" about the party's anti-graft drive. Luo could not be reached for comment yesterday.