The Chinese Communist Party said on Tuesday that it was investigating an outspoken property tycoon who accused China’s top leader, Xi Jinping, of having mishandled the coronavirus outbreak.

Party officials said the man, Ren Zhiqiang, was suspected of “serious violations of discipline and law,” a euphemism the authorities often use for corruption and other abuses of power.

Mr. Ren, a longtime party member, disappeared last month after having written an explosive essay describing Mr. Xi as a power-hungry “clown.” The essay, which circulated on Chinese social media sites, said that the party’s strict limits on freedom of speech and its silencing of the news media had exacerbated the epidemic.

[Analysis: Peaks, testing and lockdowns: How coronavirus vocabulary causes confusion.]

A brief statement about the investigation of Mr. Ren, issued by party disciplinary officials in Beijing, did not provide Mr. Ren’s whereabouts, give details about the status of his case or make mention of the essay.