The man wore a khaki uniform, a baseball cap and a camouflage ski mask, heightening the drama in the high school classroom. Because he worked as an intelligence officer, he did not disclose his name, creating even more mystery.

His presentation started with a video showing a stack of $100 bills on a mousetrap with a red skull and crossbones. “How not to fall into the trap of Russian intelligence services,” the video advised.

By the end he had gone through screen after screen of chilling examples from the past year, including one teenager who died after being turned into a suicide bomber by the Russians without his knowledge. Others would come close. And the 50 young students in the room, ages 16 and 17, would be riveted.

Think of this class, in a secondary school in the western city of Lviv, as the Ukrainian version of “Scared Straight.” The course, introduced this spring by Ukraine’s top internal security agency and the national police at high schools nationwide, aims to deter teenagers from falling under the influence of Russian operatives. They have started paying Ukrainian minors to set fires or plant homemade bombs, Ukrainian authorities say.

“I remind you that criminal responsibility in Ukraine begins at 14 years of age,” said the camouflaged man at the presentation on a recent Wednesday. “Unfortunately, this easy money can lead either to criminal liability or to death.”