JOHANNESBURG, South Africa -- South African police on Monday searched for assailants who forced a family from their car and drove off with a 4-year-old boy hanging out of the vehicle. The boy was later found dead in the abandoned vehicle.

The boy was with his sister and parents in Boksburg, east of Johannesburg, during the carjacking Saturday night, according to South African media. His mother told The Star newspaper that she tried in vain to pull her son from the car. The boy's head and body may have hit the road as the car sped away, causing fatal injuries.

"I asked them to let me pull my child out because his foot was stuck, but they just sped off and ripped him out of my hands," The Star quoted the boy's mother, Chantel Morris, as saying.

The newspaper said Morris ran after the car, screaming and pleading, and other people also ran after the vehicle, shouting "The child! The child!"

Two or three assailants were involved, according to reports.

Authorities offered a reward of nearly $5,000 for information leading to arrests in the case, which has shocked South Africans accustomed to a high crime rate.

A South African parliamentary committee that handles police affairs said such an incident undermines South Africa's gains in curbing serious crime. There had been progress in the past five years, noting an overall reduction in crimes including murder and attacks on vulnerable groups including women, children and the disabled, it said.

In a separate case, authorities said Monday that a 6-year-old boy who was reported missing after he and his father were carjacked a week ago had been found at a shelter in Johannesburg. The boy had been wandering in the streets, police said.

A group of robbers drove off with the child in the car on July 15 after severely beating his father, tying his hands and feet and leaving him, according to reports. The attack occurred in Bronkhorstspruit district, east of Pretoria, the South African capital.

The case drew national attention. Over the weekend, President Jacob Zuma appealed to the public to help find the missing boy.