New: Man being questioned is "not our prime suspect," public safety spokesman says
Group calling itself Bolt Force wants to help the police
Authorities are looking into a string of shootings along a stretch of I-10 in Phoenix
A state official says of shootings, "All of these acts are potentially lethal encounters"
The civilians – armed with guns, knives, mace and other weapons – call themselves “Bolt Force.”
Their mission: Helping authorities solve a rash of shootings along a busy stretch of Interstate 10 in downtown Phoenix and elsewhere in the Arizona capital.
They are a stealthy bunch, all dressed in black. They claim 17 members, including men and women of different races. They can be spotted stalking above highway overpasses and patrolling nooks and alleyways around Interstate 10.