A senior official at a central Chinese city court has died after 11 days in the custody of Communist Party anti-graft investigators.

Relatives of Jia Jiuxiang, who was vice president of the Sanmenxia City Intermediate People's Court in Henan province, say they suspect he was tortured in detention.

Jia's is the second mysterious death of an official during detention by the party's anti-corruption investigators in two weeks.

His brother-in-law, Zhou Qiang, said Jia died early Tuesday morning at a local hospital and that Jia's wife said his face had turned blue and his body was covered in bruises.

A man at the city government's politics and law committee surnamed Song said officials at the committee was aware of the case but he had no further details.