China is investigating a second former top military officer on suspicion of corruption, two independent sources told Reuters, as President Xi Jinping widens his campaign against deep-rooted graft in the country.

Guo Boxiong, 72, was a vice chairman of the powerful Central Military Commission until he stepped down in 2012. Another former vice chairman, Xu Caihou, was put under investigation last year for corruption.

Before their retirement, the men had been two of China's top military officers who served together under Xi's predecessor, Hu Jintao. Xi was also a vice chairman with Guo and Xu from 2010-2012, before he became head of the party and military commission chief.

Serving and retired military officers have said graft in the armed forces is so pervasive it could undermine China's ability to wage war. In one case, a senior officer has been accused of making millions of dollars from selling hundreds of military positions.

The government announced an investigation into Guo's son, Guo Zhenggang, a deputy political commissar of the military in the eastern province of Zhejiang, on Mar. 2. He had just been promoted to a major general in January.

"Guo Boxiong himself is in trouble and is being investigated," a source with ties to the military told Reuters, speaking on condition of anonymity. "The announcement about his son was a message" to the public about the father's probe, the source added, without elaborating.

A second source with ties to the military confirmed that Guo was being investigated, but provided no other details.
China's Defence Ministry did not respond to a request for comment.

Guo sat on the Central Military Commission, in charge of the world's largest armed force of around 2.3 million personnel, for more than a decade, having risen through the ranks after joining the army in 1961, according to his official biography.

In 2006 he visited the United States and met then-defense secretary Donald Rumsfeld.

The Chinese government has fuelled speculation about his fate with a commentary carried on the website of the Communist Party's People's Daily late on Mar. 2, headlined: "You know what signal the fall of Guo Zhenggang sends."

It was widely picked up by other Chinese media.

"When it comes to fighting corruption in the military, the best part of the show is yet to come," the commentary said, prompting a flurry of responses on Weibo, China's answer to Twitter, that the father was the real target.

INVESTIGATIONS WIDEN

The government has developed a habit of dropping hints in state media about who is in trouble before formal announcements are made.

Beijing has announced investigations into more than a dozen senior military officials on serious corruption charges, 14 of them on Mar. 2, including Guo's son. Many of those implicated have ties to the scandal involving Xu.

The news comes shortly before the annual meeting of China's parliament, the National People's Congress, which opens on Mar. 5. Corruption is likely to be a major talking point, though no new measures to fight it are expected to be announced.

The Defence Ministry, in its own commentary issued on Mar. 2, said its efforts were paying off.
"The intense publicity surrounding these measures lets us see ... the military's iron-handed determination to fight corruption," it said, dismissing what it called "certain doubting voices on the Internet" that the campaign is not serious.
Rumours that Guo and his son were being investigated for corruption have swirled in the overseas Chinese press over the last few months.
Reuters has not been able to reach either Guo for comment.

Xi heads the Central Military Commission and has made weeding out corruption in the military a top goal.

He has vowed to target high-ranking "tigers" as well as lowly "flies" in a broad campaign against corruption which has intensified since Xi became president.

While the drive has ensnared senior figures, internal Communist Party harmony and respect for elders still hold sway, and Xi secured the blessing of his still influential predecessor before launching an investigation last year into a former senior aide to Hu.

The anti-graft drive in the military comes as Xi steps up efforts to modernise forces that are projecting power across the disputed waters of the East and South China Seas, though China has not fought a war in decades.

China intensified its crackdown on corruption in the military in the late 1990s, banning the People's Liberation Army from engaging in business. But the military has been involved in commercial dealings in recent years due to a lack of checks and balances, military analysts have said.