By Gabriel Stargardter
RIO DE JANEIRO, BRAZIL - Before Brazilian prosecutors could conduct an inspection last year of the prison considered the country's worst, its warden had to clear their visit with the jail's de facto authorities: in-house prison gangs.
As Brazil's incarcerated population has surged eight-fold in three decades to around 750,000 inmates, the world's third-highest tally, its prison gangs have come to wield vast power . . .