Story highlights The father of a slain 7-year-old isn't cooperating with police, Chicago's top cop says

"I'm worried that the next shooting will occur in retaliation," the police superintendent says

A broken system and a rampant gun flow fuel the violence, he says

(CNN) When a city has eight killings in two days, including the death of a 7-year-old boy, something is seriously wrong with the system.

That's what Chicago's police chief said after a spate of bloodshed that tormented the city over the weekend.

"We need to repair a broken system," Police Superintendent Garry McCarthy told reporters Sunday. "Criminals don't feel the repercussions of the justice system."

Take, for example, the death of 7-year-old Amari Brown. McCarthy said the boy was the unintended victim of a bullet meant for his father, a ranking gang member.

The system failed Amari, the police chief said. Amari's father, who has been arrested 45 times and has a lengthy criminal record, should not have been on the streets, McCarthy said.

Read More