BEIJING — Gu Kailai, the wife of deposed Politburo official Bo Xilai, and one of her household aides have been formally charged with “intentional homicide” in the case of a deceased British businessman, Neil Heywood, the official Xinhua news agency reported Thursday.

The brief Xinhua dispatch said Gu and the aide, Zhang Xiaojun, were charged in a court in Hefei, in Anhui province, after prosecutors interrogated them and spoke to their defense team. The two were arrested on suspicion of murder last spring, triggering what has become China’s most dramatic political upheaval in more than two decades.

Xinhua, quoting unidentified investigators, alleged that Gu and Zhang poisoned Heywood after Gu and Heywood had a business conflict that also involved her son. The report said Gu believed Heywood was threatening her son.

“The facts of the two defendants’ crime are clear, and the evidence is irrefutable and substantial,” the Xinhua report said. “Therefore, the two defendants should be charged with intentional homicide.”

There was no mention by Xinhua of the fate of Bo, who was considered a high flier in the Communist Party hierarchy until his abrupt dismissal as party boss of the city of Chongqing in March. Neither Bo nor his wife has been seen publicly in recent months.

Bo, once seemingly destined for a promotion to the powerful Politburo Standing Committee, apparently has been rendered persona non grata by his potential involvement in the murder case. The saga — unfolding as the Communist Party prepares for a once-in-a-decade leadership transition — has upended China’s careful political choreography and has exposed infighting and rifts within the ruling party’s top ranks.

Xinhua said the court in Hefei “will hold a trial on a day to be decided.” Based on Chinese practice, it is likely to be soon. There was no explanation as to why Anhui province was selected for the prosecution, because the alleged crime took place in Chongqing. But politically sensitive cases are often moved to distant locations.

The son allegedly at the center of the scandal is not named in the report but is believed to be Bo Guagua, a recent graduate of Harvard University’s Kennedy School of Government. He is believed to be in the United States.

“Worrying about Neil Heywood’s threat to her son’s personal security, Bogu Kailai along with Zhang Xiaojun, the other defendant, poisoned Neil Heywood to death,” Xinhua alleged. (Since the beginning of the case, official announcements have referred to Gu Kailai by the surname “Bogu,” combining Bo’s name with her maiden name, Gu. The practice is not common in China but is sometimes used by Chinese abroad.)

Despite a wall of silence surrounding the case, senior Chinese officials speaking to diplomats, visiting academics and others have hinted that they wanted it settled before the opening this fall of the 18th Party Congress, which will select a new president and prime minister and fill seven vacant slots on the Politburo Standing Committee, which effectively runs the country.