Sharmaine Lincoln issued to appeal urging the community to unite as one to get justice for her 15-year-old son.
She features in a video appeal alongside Keon's twin sister Kiarah. The video also features family friend Pastor Neville Popo.
WATCH: Family of murdered Keon Lincoln issue appeal to help catch his killers
Sharmaine said: "I have lost a part of me, my heart has been ripped out of me.
"How do you live after your child has been taken away from you? It’s every parent’s worst nightmare.
“What he could have done to warrant this type of brutality doesn’t make sense. He can’t have been taken like this and nobody is punished for it.”
Keon was attacked in Linwood Road, in the Handsworth area, on the afternoon of Thursday, January 12, by a group of youths.
West Midlands Police officers have already arrested five boys in connection with the killing.
Boys aged 16, 15 and two 14-year-olds remain in custody for questioning, while another 14-year-old has been released under investigation.
Detective Chief Inspector Alastair Orencas, who is leading the investigation, said: “The answer to this investigation lies in the community.
"In the 24 years that I have been serving in the police service, and I don’t say this lightly, this is the most gratuitous use of violence seeing a combination of knife and gun attack which ultimately killed Keon.
“We know that the nature of this crime where it involves a young man that has lost his life and young men that have committed the crime means that the information and intelligence is highly likely to rest with the younger community, but also their parents.
“I know it’s not easy to come forward but there is a moral obligation – imagine this was your friend or your son, you’ve got to come forward.”
Anyone with information is urges to call West Midlands Police on 101, or Crimestoppers anonymously on 0800 555111.