The death of disgraced former general Xu Caihou on Sunday did not mean the end to graft investigations into people linked to him, the military said yesterday, vowing to press on with a crackdown on corruption. In a commentary on a website affiliated with The PLA Daily , the authorities pledged to keep up the "zero tolerance" approach towards corruption, saying cases related to Xu's would not be "left unsettled". The pledge came hours after Xinhua reported late on Sunday that the former vice-chairman of the Central Military Commission had died at age 71 of multiple organ failure and bladder cancer. In another statement on the website, the military procuratorate said Xu's cancer was diagnosed on February 4, 2013, and he was sent to the PLA General Hospital in Beijing, where he was kept under surveillance and treated by medical specialists. Both the Xinhua report and the procuratorate's statement said the case against Xu, who is so far the most senior military official targeted by President Xi Jinping's ongoing anti-graft campaign, had been dropped. The commentary in The PLA Daily said Xu's case had been a "deep lesson" for the army. But it added that the investigation against Xu was "one of necessity" and an example for others in the PLA's ongoing, hard-hitting campaign. "In order to build a strong army of a great power, how can [the army] allow corrupt people to escape?" The timing of the announcement of Xu's death prompted speculation that he might have died much earlier and that the news may have been kept secret to avoid overshadowing the National People's Congress, which ended on Sunday morning. A Beijing-based senior colonel told the South China Morning Post that he heard Xu was "in extremely critical situation more than a week ago, but medical staff had spared no efforts to keep him alive". A source close to the Guangzhou Military Region, where Xu's daughter, Xu Sining , was working, told the Post it would have been out of the question to announce Xu's death while the congress was still under way. "Xu was expected to die many days ago, but it would have been impossible to announce his death at the time because there is a rule that no one and nothing can be allowed to shift the focus away from the NPC," the source said. There was also discussion about the fate of other senior officials closely connected to Xu. A Shanghai-based colonel said Xu's death would help Xi, who is also chairman of the CMC, to focus on the anti-corruption investigations against retired general Guo Boxiong . Guo's son, Guo Zhenggang , is among the 14 senior military officials that the authorities named two weeks ago as either under investigation or having been convicted of graft. "The public previously demanded an open hearing for Xu. That might have embarrassed President Xi because it's possible Xu might have revealed secrets or inside stories if he didn't want to cooperate with the authorities," the Shanghai source said. "As soon as Xu's case is wrapped up, Xi will feel free to target other big 'tigers' like Guo," he said, referring to the president's vow to go after corrupt officials of all ranks.