The family's 16-year-old maid was also killed.

Chen Yiming, chief judge of the intermediate court's No.2 criminal court in Linxia Hui Prefecture of Gansu Province, was found face down in a pool of blood in a bedroom of his fourth-floor apartment.

The little boy, bound to a chair with his hands tied behind him and his mouth taped, apparently died of a head wound.

The judge's wife and the maid were kneeling on the bathroom floor with their hands trussed up behind them by adhesive tape.

It was not clear how they died.

The judge's daughter-in-law - mother of the murdered boy - found the gruesome scene when she arrived at the apartment about 8pm on Tuesday.

A local newspaper said the daughter-in-law had phoned the home number on her way home between 7pm and 8pm, but got no answer.

Chen and his wife were both 58.

A doctor from the local first aid center, who went to the scene, said Chen's room had clearly been ransacked.

He said all four victims were dead when the medical team arrived at the apartment with the police.

There was an obvious wound in the grandson's head.

The doctor said the boy's body was still warm, but his breathing had stopped.

Local police said they have found no motive for the killings.

The intermediate court has reported the case to the provincial higher court.

Neighbors said the Chens were kind people and had no apparent conflict with others.

Chen was scheduled to retire in two years, according to China's age limit for civil servants. He had been acting as the court chief since 1994, two years after being appointed to the court.

The Chen murders are the second family murder of a government official in just over two weeks.

On November 27, Wen Jiangang, governor of Xingren County in southwest China's Guizhou Province, was found murdered in his home, along with his wife, son, mother-in-law, elder sister and the family babysitter.

Local police detained a suspect named Cao Hui early this month, and say the man, 42, has confessed to the murders.