An international coalition of law enforcement officials announced Tuesday that they had ensnared alleged criminals around the world after duping them into using phones loaded with an encrypted messaging app that was controlled by the FBI. The audacious effort, led by the FBI, Australian police and a host of European law enforcement agencies, gave the officials a window into the conversations of criminal networks as people traded photos of cocaine packed into shipments of fruit, plotted robberies and put out contracts for killings. Law enforcement officials — some of whom on Tuesday could barely contain their glee — announced they had arrested more than 800 people and gained an unprecedented understanding into the functioning of modern criminal networks that would keep fueling investigations long past the coordinated international raids that took place in recent days... For nearly three years, law enforcement officials have been sitting in the back pocket of some of the world’s top alleged crime figures. Custom cellphones, bought on the black market and installed with the FBI-controlled platform, called AN0M, circulated and grew in popularity among criminals as high-profile crime entities vouched for its integrity.