It was finally the turn of the capital to see its first senior official ensnared in President Xi Jinping's relentless anti-corruption crackdown - a day after Shanghai announced that a vice-mayor was being investigated. The toppling of two senior officials in China's political and economic capitals, on consecutive days, show that Xi's sweeping campaign is not letting up. Yesterday, the Communist Party's discipline watchdog said Lu Xiwen , the deputy party boss of Beijing municipality, was being probed for "severe disciplinary violations", a euphemism for corruption. Lu's downfall means that each of China's 31 provincial-level administrative areas now has at least one "tiger" - Xi's metaphor for powerful officials - who has fallen from grace. The Central Commission for Discipline Inspection (CCDI) has accelerated its clampdown recently. Five senior officials - three in provincial-level governments and two in state-owned enterprises - were placed under investigation this month. In the financial industry, more than a dozen powerful figures have been taken away for investigation in recent months, following the meltdown of China's stock market. The anti-graft campaign launched by Xi three years ago has netted thousands of officials nationwide and tracked scores of others who fled overseas. Lu, 60, has worked for the capital since graduating from university. Before becoming deputy secretary of the municipal party committee, Lu governed the city's Xicheng district for seven years and spent another seven years as head of the party committee's organisation department - a crucial body in charge of personnel arrangements. Lu last appeared in public on Friday. Lu's investigation was made public the day after Ai Baojun , a vice-mayor of Shanghai, was said to be facing a graft investigation. Like Lu, Ai was the first disgraced "tiger" in his city under the current crackdown. READ MORE: Under investigation: Shanghai vice-mayor Ai Baojun becomes city's first 'tiger' caught in anti-corruption spotlight Financial news outlet Caijing reported that Ai's wife, who died a week ago from kidney failure, was investigated for stock market manipulation during the mainland's financial turmoil in the summer. Wu Muluan, a professor of Asian and Policy Studies at the Hong Kong Institute of Education, said Xi's crackdown on graft would maintain its momentum at least until the semi-leadership transition in 2017. "Some people thought he would stop after [security tsar] Zhou Yongkang was jailed, but that's not the case. If he stopped then, [the crackdown] would be merely a power struggle. But he has resolved to carry on," Wu said. Beijing party boss Guo Jinlong applauded the CCDI's sudden decision. He told local officials yesterday that the city's leadership "strongly supports the [party leadership's] decision".