Jonathan Matondo died from a single gunshot wound to his head
Detectives have been working with children as young as five to try to stop them becoming embroiled in Sheffield's gang culture.
The issue of gang-related rivalry between groups from two postcode areas emerged after the killing of 16-year-old Jonathan Matondo last year.
Supt Andy Barrs told BBC News that young children could be introduced to gangs as look-outs for drug dealers.
Officers are working in schools to steer young children away from gangs.
Mr Barrs said: "Part of the work we have been doing in Sheffield with our partner agencies is to work with young people, as young as around five or six, getting into schools and getting the message out, the negative message about gang membership.
"It's not cool, it's not big to be in a gang and [we have been] trying to dissuade young people about gang membership.
"We have found in the past that young kids can get into gang culture in being look-outs for drug dealers etc."
Culture change for the young
Pastor Andrew Rashford-Hewitt, from the Seventh-day Adventist Church, said he believed early intervention was the key to fighting gang crime.
He told BBC News: "We can't leave things to just take place haphazardly.
"Appropriate positive intervention, as early even as six, will help.
"Without that there are influences that may appeal to young people as young as six to get them into the avenue of crime that later becomes serious crime."
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