BEIJING — Gu Kailai, the wife of disgraced Chinese politician Bo Xilai, has been formally charged with murder in the death of a British businessman, state media reported Thursday.

Gu and a person previously described as a household employee, Zhang Xiaojun, are accused of poisoning Neil Heywood last November after conflicts arose "over economic interests" and worries about Heywood's "threat to her son's personal security," according to the state news wire Xinhua.

While the indictment isn't a surprise — state media reported in April that the two were suspected of killing Heywood, 41, and had been "transferred to judicial authorities" — it signals a step forward in events that have shocked the country's highest levels of power.

The Xinhua report stressed that authorities are confident about the case against Gu; a murder conviction could bring the death penalty. The Chinese Communist Party almost certainly has determined the outcome. Chinese trials aren't open to the public, though relatives may be allowed to attend.

While Xinhua said a trial date in China's eastern Anhui province hadn't been set, a Reuters report quoted a family lawyer as saying it probably would start Aug. 7 or 8.

It remains unclear what will happen to Bo Xilai, who wasn't named in the Xinhua release.

Gu, a prominent attorney, is the daughter of a prominent revolutionary general, and her husband the son of a prominent party elder. Until recently, Bo was widely seen as a leading candidate for a slot on the nation's ruling Politburo Standing Committee. But he was stripped of his position as the party chief in the sprawling southwestern city of Chongqing and booted from the 25-person Politburo in the months after his former police chief fled to an American consulate in February.

Sources in Chongqing later claimed the recently demoted police chief, Wang Lijun, had decided to bolt from the city after a confrontation with Bo sparked by his airing of suspicions that Gu had killed Heywood. After emerging from the U.S. consulate in Chengdu, northwest of Chongqing, Wang is thought to have cooperated with Chinese government investigators.

Bo hasn't been charged with any crime. In announcing his removal from the Politburo in April, Xinhua said only that he stood "suspected of being involved in serious discipline violations."

How and when to resolve his fate is a particularly sensitive issue given the upcoming Communist Party Congress, which is scheduled for before the end of the year and will usher in the once-in-a-decade transition of top leadership.

Heywood reportedly functioned as a middleman for the family, arranging business deals and allegedly working to get Bo and Gu's son into the Harrow School, an elite British boarding school. There has been rampant speculation that Heywood helped Gu transfer large amounts of money out of China.

Heywood's death in a Chongqing hotel room initially was reported as due to natural causes, related either to overconsumption of alcohol or heart complications, and his body was cremated.

Another reported former member of Gu's inner circle, French architect Patrick Henri Devillers, flew to China last week from Cambodia to serve as a witness in the investigation. Chinese officials had requested that Devillers be extradited.

During his reign as the party secretary of Chongqing, Bo cultivated a populist appeal and, relative to the typically button-down world of Chinese politics, brash ambition.