Three Chinese lawmakers linked to the defense sector have been removed from their seats, the country’s state media reported Wednesday.

No explicit reason for their dismissal was given, but outside analysts suspect it had something to do with the sudden and shocking purge of China’s top general, Zhang Youxia.

Zhang was ousted from his perch as vice chair of the Central Military Commission (CMC) in late January, ostensibly for “severe violations of party discipline and state laws,” which is usually taken as shorthand for either corruption or falling out of favor with the dictatorship.

Zhang was second only to dictator Xi Jinping in power, and he was a longtime friend and ally of Xi’s who seemed relatively secure in his position.

The three lawmakers dismissed this week were Zhou Xinmin, formerly head of the state-owned enterprise that manufactures most of China’s manned and unmanned military aircraft; nuclear weapons researcher Liu Cangl; and nuclear engineer Luo Qi, who was chief engineer at the state-owned China National Nuclear Corp.

All three men were members of the Standing Committee of the National People’s Congress, China’s rubber-stamp facsimile of a legislature. The Standing Committee offered no explanation for their departure.

The sacking of these three was even more sudden and secretive than Zhang’s ouster. Zhou’s company, Aviation Industry Corp. of China (AVIC), held an anti-corruption meeting the day before his firing was announced. Another AVIC executive was booted from the Chinese Communist Party for corruption exactly one year ago, fueling suspicions that Zhang was suspected of corruption as well – or that at least it was the excuse for getting rid of him.

There are three major theories behind the downfall of Zhang and other officials linked to the Chinese military-industrial complex. The first, and simplest, is that Xi really is dealing with an appalling amount of corruption despite years of conducting vigorous anti-corruption purges and may have felt Zhang’s corruption was so massive that he needed to get out in front of it.

The second theory is that Xi is whipping the People’s Liberation Army (PLA), including its research division and nuclear forces, into shape for an invasion of Taiwan. This theory holds that Xi is sacrificing short-term command and control to build a tighter chain of command over the next few years.

The third, and most provocative, theory is that Xi sniffed out a coup attempt, perhaps led by Zhang, and launched a preemptive strike against the would-be putschists. In that scenario, the three lawmakers expelled this week would have made for plausible co-conspirators.

The coup theory appeals to some observers because purging Zhang was such a huge and unprecedented step for Xi – a move guaranteed to damage the PLA’s morale and compromise its operational structure for years to come. Zhang was one of the very few senior Chinese officers with combat experience, and Xi valued him highly enough to persuade him to remain at his post for years beyond the normal retirement age of seventy.