In ancient times in China many have been engaged in mass murder. It was a sacrifice offered to a deceased emperor or prince.
It is believed that the noble persons must be conveyed with all his wealth in the other world, to live luxuriously and there, surrounded by all the services of advisers and their employees. Therefore, along with the burials of the rulers it included whole herds of bulls, sheep, dogs, pigs and tigers. Slaves who were buried alive in the ground or were incinerated were also victims to the burial of the rulers.
When the ruler died from the Qing Dynasty during the VII century BC, along with him were buried alive 177 people, including three representative of the noble families. Also included were various articles of jade and bronze, including weapons, precious ornaments, so not to be deprived of anything in their life in heaven.
Therefore the imperial tombs in China were built huge, in order to be able to accommodate all the treasure and the ruler's entourage.
If he was married, he would certainly need the presence of his wife of that world. So going along with the custom and deceased rulers they would forcibly kill their wives. For example, with Emperor Shi Huang, who lived in the III century BC, were buried so were all his wives, which had no children.
Around the middle of I millennium BC, human sacrifice almost ceased.