Nine people have been charged in connection with a series of firebombings in Mill Woods last year, Edmonton police said Monday.
Eight of the males charged were under the age of 18 at the time the incidents took place, and so cannot be named under the Youth Criminal Justice Act.
A ninth man, Amir Ahmed Qureshi, 20, turned himself into police on Sunday night after police issued a warrant for his arrest.
Qureshi has been charged with four counts each of unlawfully making or possessing explosives, possession of incendiary material, possession on an explosive with intent, arson with disregard for human life, and one count of uttering threats.
The youths face varying numbers of explosives and arson charges.
The investigation began in March 2008 after a number of homes in Mill Woods were hit by Molotov cocktails.
The conflict started between two teens and quickly escalated into a conflict between two rival groups of teens, said Southeast Division Supt. David Veitch.
"I believe it was two individuals that were fighting, and then it just kinda got out of control from there, kind of tit for tat, back and forth, and resulted in, I think, a vehicle being damaged initially," Veitch said. "Then after, it escalated from there."
Police tried to mediate a solution last summer, but the violence continued when a neighbour's house was targeted by mistake, police said.
The investigation is continuing, Veitch said, and police expect to lay more charges.