beijing senior military officer sit china powerful central military commission head president xi jinping question suspicion corruption three source familiar situation say fang fenghui chief joint staff department people liberation army replace late last month official word happen whether take another post retire fang fenghui question regard economic problems source tie leadership tell reuters economic problems often use euphemism corruption china another source familiar situation say detain suspicion corruption say second source also speak condition anonymity third source also confirm fang question clear question would lead formal indictment chinese officials sometimes question informally release china defence ministry respond request comment whether fang detain question also possible reach fang representative comment unclear allow retain lawyer fight corruption military focus xi broad crackdown deep-seated graft problem warn serious could affect rule communist party grip power dozens officer investigate jail include xu caihou guo boxiong former vice chairmen central military commission guo jail life last year xu die cancer 2015 could face trial 11-man central military commission overall charge china military head xi make senior military officer monthly news conference last week defense ministry spokesman ren guoqiang decline comment fang give another position wen ask fang ren say aware fang turn 67 next year age many chinese officials retire last public appearance aug. 21 meet senior thai military officer beijing also meet joseph dunford chairman u.s. joint chiefs staff aug. 15. fang also part xi delegation meet u.s. president donald trump trump mar-a-lago estate florida april question fang come ahead next month once-every-five-years communist party congress xi look cement tight grip power party already begin military reshuffle connect congress announce last week new chiefs army air force official people liberation army daily say last month military need guard corruption rear head warn arrow put back quiver serve retire officer say graft arm force pervasive could undermine china ability wage war anti-graft drive come xi step efforts modernize force project power across dispute water east south china seas although china fight war decades senior chinese military officer question suspect graft source