Seven-year-old Brajon Brown is clearly a child. He hasn’t committed a crime, though he talks about it. His 12-year-old brother, Malcolm also is not in a gang – at least not one police recognize. He runs with a “crew” of friends formed when Malcolm was 9. Boston police call them “wannabes” and say they usually don’t show up on police radar until they are teenagers and committed to gangs known for more serious crimes. Some experts say Boston neglects such gangs, allowing momentum to build for a coming crime wave that would dwarf the record violence of the mid-1990s. Malcolm, who says the young males in the crew protect their territory by beating up challengers, faces charges in the beating and robbery of a boy earlier this year. “When you look into the eyes of a kid like that, in three or four years, you know he could take a life, no problem,” a former prosecutor and community activist says. He estimates that dozens of gangs like Malcolm’s – semi-organized groups of middle and elementary school-age youth who mimic the actions of older gangs – operate in Boston. Last year, 49 of 102 city-run youth programs allowed only participants 13 or older. And of 180 young people who received city counseling and intervention services, only 49 children were preteens. Stressing the diversion of preteens from lives of crime, Boston’s mayor launched an effort this year to enroll every child between 8 and 14 in a summer program. Teams of city workers knocked on more than 1,700 doors in attempts to reach families who need help. An official says 233 households signed up for services, but he doesn’t know how many were for preteens. Brajon, meanwhile, already walks the streets as if he owns them, slapping pay phones off the hook as he passes and knocking items from first-floor window ledges.