By Jim Williams

CHICAGO (CBS) — A Chicago family is pleading to find the killer of a 3-year-old boy. The reward for information leading to the killer’s capture has been increased to $13,000, but it offers little comfort to Mekhi James’ heartbroken family.

The boy’s mother was so overcome she had trouble breathing.

“My boy, my boy,” said Myesha James. “He means the world to me, and I can’t even put in words, that’s why I keep saying my boy. I can’t even say what he means to my world.”

Mekhi was shot to death Saturday night in Austin. He was in a car with his step father, who police say was the gunman’s target. Wednesday afternoon the step father, who didn’t give his name, said he can’t understand why anyone would shoot at him.

“I wasn’t out here like that,” he said. “I was working, doing what I was supposed to do. I didn’t know anyone had anything against me.”

The Reverend Ira Acree, who is close to Mekhi’s grandparents, said the reward to find the killer is now up to $13,000.

“We are asking if anybody knows anything — and we really do believe you do — about the whereabouts of this killer, speak now. Please speak up. If you break the silence we can end the violence,” he said.

Gun violence over this Father’s Day weekend wounded more than 100 and killed nine, including their three year old boy.

“It’s devastating. It’s painful, and it’s hurtful when it hits home. And it hit home with Mekhi,” said one family member.

“Mekhi was a beautiful, well mannered boy. Whoever did this needs to turn yourself in. It needs to be on your soul,” said family member Rebecca Lindsay.

“My baby boy. That’s all I can say. He’s gone,” said Myesha James.

Mekhi’s mother said even if the killer is found and sentenced to 1000 years in prison, it won’t bring her son back.