Several of Malachi's friends are believed to have been watching when the gun went off - with many rushing to his house after they realised what had happened.
"There was about 40 to 50 kids outside," said Ms Stephens. "I guess these were the kids that were watching on live that live in the area. I guess when it happened they just ran over here."
"This is just a pain that will never go away," she added. "He was my only son. He was just only 13. Just the thought of me seeing him on the floor will never leave my brain."
Ms Stephens said she was unsure how her son had got hold of the gun, but believed he may have been given it by a friend.
Malichi's step father Ernest Stephens said: "It can happen to the best parents...it can happen to the best people. The best ones that loved their kids, you know?"