General Zhang Yang, the former head of the Chinese military's political work department, was found dead at his home on November 23, the news agency said.
Xinhua said investigators found Zhang had seriously violated party discipline and broke the law by allegedly giving and accepting bribes as well as possessing a huge amount of money, the sources of which he could not account for.
He was allowed to stay at home during the early stages of the investigation, the report said.
Zhang was a member of the Central Military Commission, which runs the two-million strong People's Liberation Army.
'Extremely despicable'
In a scathing commentary published by the People's Liberation Army Daily Tuesday, the paper said he "wanted to evade punishment by party discipline and state law by committing suicide -- such behavior was extremely despicable."
"By escaping from judicial and possibly disciplinary penalties once and for all, the officials suspected of corruption can not only preserve their titles and honor, but also preserve the material gains they have made for their families, since their illegal income will no longer be confiscated," Lin wrote. "Considering the astonishing sums of money an official can obtain through corruption, that's a good deal for them and their families."
Ramped-up investigations
While Xi has been praised for going after "tigers" as wells as "flies" -- high and low-ranking officials -- some critics have accused him of using the campaign to shore up his absolute control over the Communist Party and purge his opponents.