MEXICO CITY — The case has caused a wave of anguish: A 6-year-old boy in northern Mexico murdered and a group of five adolescents, who the authorities said were playing a game of “kidnap,” apprehended for the crime.

But three of the suspects, a 12-year-old boy and two 13-year-old girls, will not face imprisonment because of their ages, and that has unleashed a more complex set of emotions.

Some demanded changes to the law that sets restrictions on the incarceration of very young offenders while others denounced a lack of social and family programs that could help prevent such crimes.

On Saturday, the body of Christopher Raymundo Marquez Mora, 6, was found buried in a ditch near a stream in a poor neighborhood of Chihuahua, the capital of Chihuahua State.