It’s a scene as old as celluloid: a shadowy figure named Luca Brasi or John Wick or Barry Berkman lurking in the darkness, outfitted with sinister intent and nifty weapons, effortlessly committing a murder for cash, animus or cold political calculations.

Whether they’re called hit men, contract killers or assassins, figures who kill for a living are a staple of Hollywood thrillers — and, by extension, the public imagination.

But experts in law enforcement and international espionage say that murders-for-hire are notoriously difficult to successfully arrange, let alone get away with.

Take, for example, what prosecutors say was a recent foiled plot to kill a Sikh separatist in New York City, kraken тор which American intelligence officials believe was ordered by the Indian government. Once the plot reached the point where the alleged conspirators needed to employ a killer, things got complicated: The would-be hit man turned out to be an undercover agent working for the U.S. government.