A drug addict who was accused by her mother of being under the influence of narcotics when she allegedly killed her 5-year-old son at home was detained in Kaiping city, eastern Guangdong province, on Sunday morning, Guangzhou Daily reported.
The addict's mother told police that her daughter had allegedly tied up the boy in the kitchen, covered his face in plastic and locked the door.
Police found the child with his hands and feet tied with rope when they arrived in the apartment.
The grandmother told police that her daughter, surnamed Huang, 22, had taken drugs before allegedly killing her son.
Police said they found implements for drug use in the home.