Reporter

Rating: (3 stars)

Thanks to the death threats that greeted the 2006 publication of Roberto Saviano’s first book, “Gomorrah,” a novelistic but deeply reported exposé of the organized-crime underworld of Naples — made into an excellent 2008 film and subsequent TV series — the Italian writer now must live under constant armed guard. His 2016 book “The Piranhas,” a more traditional novel (though one still inspired by true crime) about Neapolitan mobsters who are not yet out of their teens, has not changed any of that.

Watch the new movie based on Saviano’s book, and you’ll understand why.

Centering on Nicola, the charismatic 15-year-old leader of an adolescent gang, and his meteoric rise in the Mafia-like ranks of the Camorra crime syndicate, “Piranhas” is no documentary, but it plays out with a deadpan style that is deeply unsettling.

Nicola, played by boy-band-handsome newcomer Francesco Di Napoli, is no thug, but an amoral charmer. Loosely based on the late Emanuele Sibillo, a teenage mobster who was killed in 2015, Nicola and his pimply faced pals quickly ingratiate themselves with the criminal establishment of Naples by selling drugs on the street before taking advantage of a power vacuum. When several older Mafiosi are arrested during a wedding, Nicola and his crew step into the resulting void, shooting up whatever rivals remain, if they have to, and boasting about their exploits on social media.

They are kings of the world, for a minute, until it comes crashing down.

Director Claudio Giovannesi, working from a screenplay co-written with Saviano and Maurizio Braucci (a writer on the film “Gomorrah”), elicits powerfully believable and naturalistic performances from his young cast of mostly nonactors, telling a story that is brisk and unfussy, yet polished. It glamorizes nothing and will almost certainly irritate the people who have inspired its rogue’s gallery of opportunistic young strivers.

Nicola may be beautiful to look at, but his portrait in “Piranhas,” along with the ugly, violent world he inhabits — a real, if lightly fictionalized one — is profoundly unflattering.

Unrated. At Landmark’s E Street Cinema. Contains obscenity, violence, drugs and nudity and sexuality. In Italian with subtitles. 105 minutes.