Heywood, a 41-year-old businessman based in Beijing, was found dead last November in a hotel room in Chongqing.
Until now, the Heywood family has resolutely maintained that there was nothing suspicious about the British businessman's death.
On Tuesday however, the Chinese government said Gu Kailai, the wife of the city's Communist party chief, Bo Xilai, was "highly suspected" of having murdered him.
Speaking from her house in Streatham, south London, Ann Heywood, his 74-year-old mother said the news had come as a "total shock".
"All I want to say is that I am shocked at the news, but I cannot talk any more," Mrs Heywood said. ..read more