The Chinese widow of a British businessman thought to have been murdered in a case that has rocked China’s political establishment has been gagged by local police, a source with direct knowledge of the matter said.

Neil Heywood, 41, was found dead in his hotel room in China’s southwestern city of Chongqing last November. The family initially did not suspect foul play. But in a stunning twist, state media announced that Gu Kailai, wife of Chongqing’s disgraced Communist Party boss Bo Xilai, and a household assistant were “highly suspected” of killing Heywood and have been detained.

Heywood’s widow, Wang Lulu who lives with her two children in a gated community of expensive villas on the outskirts of Beijing, has not commented publicly about the case. State media cited a dispute over unspecified “economic interests” between Gu and Heywood.

“Police officers questioned her recently and warned her not to speak to…