Three 14-year-old boys arrested on suspicion of murdering 15-year-old Keon Lincoln have been released under investigation, police said.
Two other boys, aged 15 and 16, remain in custody as officers have been granted extra time to question them.
Keon was "set upon" at about 15:30 GMT on Thursday on Linwood Road in Handsworth, Birmingham, and later died in hospital.
A post-mortem examination revealed he was shot and stabbed to death.
West Midlands Police said its investigation into the "heart-breaking" death "continues at pace".
On Monday, Keon's mother Sharmaine Lincoln made an emotional appeal pleading with the local community to "help us understand why this has happened".
Det Ch Insp Alastair Orencas said: "I know there are many concerns and worries within our communities, but please be assured we're doing all we can and will not give up in our pursuit to get justice for Keon and his family.
"We have a dedicated team working on this 24/7.
"However, I still need your help - the community will be vital in helping us - I need anyone who's not yet spoken to us, to do so, as soon as they can."
He urged people to "do the right thing" and come forward with information.