A mother, who allegedly beat her four-year-old son to death because he wet the bed, has been charged with assault by the Minhang District Prosecutors' Office in Shanghai.

The father of the boy, surnamed Qi, has also been charged with tampering with evidence after he helped dump the child's body even though he knew his wife had killed the boy.

Prosecutors said the boy was a happy, pleasant and healthy child. The mother apparently beat her son as an act of vengeance against her in-laws who loved their grandson and argued with his mother.

The woman, surnamed Shan, a 25-year-old Anhui Province native, married Qi, a Shandong Province native, in 2003 and their son Le Le was born on July 1, 2004.

Shan was unhappy living with her parents-in-law. She felt they were distant with her and the young couple and their son came to Shanghai last year as migrant workers.

Qi told prosecutors that his wife was hot-tempered and always vented her spleen on the boy after she argued with the parents-in-law. She regularly beat the child with a wooden stick or a metal clothes rack.

A neighbor surnamed Lei said that she often heard the mother shouting at the little boy who could then be heard crying in his room.

Early in the morning on May 29, Le Le wet his bed and Shan forced him to kneel on the floor. Qi could not persuade his wife to stop the punishment and went back to his bed and slept, prosecutors said.

While the boy was kneeling on the floor his mother repeatedly kicked him in the stomach. The little boy wet himself again during this torture and the mother forced him to stay kneeling for 13 hours without a break and without food.

That night the mother found the boy lying on the floor but no longer breathing. The father wanted to send the boy to hospital but again the mother ruled. There was no point in sending the boy to hospital - he had already died, she said.

Shan put her son's body into a bag and then knelt in front of her husband begging him to help her throw the body away. They took the bag with their child's body in it to a remote part of Yuanjiang Road and threw the bag into a river.

On June 1, two young men fishing for crayfish found the bag and opened it. When they saw the child's feet they immediately called the police.

A police doctor said the boy had died from a ruptured liver caused by external force.

The couple was quickly arrested. Their neighbors had heard the assaults but said nothing until it was too late.

(Shanghai Daily July 22, 2008)