Gu Kailai probably dreamed of a grand destiny for herself when she married the princeling Bo Xilai 26 years ago.
But the former high-flying lawyer, 53, is now under arrest, suspected of being involved in the murder of a British businessman.
The central government said late on Tuesday that she had been 'transferred to judicial authorities'.
It followed the discovery of 'evidence that pointed strongly' to her involvement in the death of Neil Heywood, 41, in November.
A source told the South China Morning Post that Gu was under investigation by the Central Commission for Discipline Inspection in Beijing before she was transferred to police custody.
It is a spectacular plunge from grace for a woman who achieved notable successes in her legal career and married Bo, an heir apparent to membership of the all-powerful Politburo Standing Committee
Her downfall became public in February when Wang Lijun, the former Chongqing police chief and key Bo ally now under investigation himself, sought refuge in the US consulate in Chengdu.