Federal prosecutors in Brooklyn charged a 21-year-old Bangladeshi man with conspiring to blow up the Federal Reserve Bank of New York, saying he tried to remotely detonate what he believed was a 1,000-pound bomb in a van he parked outside the building in Lower Manhattan on Wednesday.

But the entire plot played out under the surveillance of the Federal Bureau of Investigation and the New York Police Department as part of an elaborate sting operation, according to court papers.