Prosecutors in southern Russian are investigating a 16-year boy on suspicion of posting remarks on social media in support of the 1939 Nazi invasion of Poland.

A spokeswoman for the investigative committee in the city of Astrakhan said Wednesday that the alleged behavior was in violation of laws forbidding the justification of war crimes.

Legislation criminalizing the rehabilitation of Nazism was adopted last year and envisions penalties ranging from fines to three years in prison. If the case goes to trial, it will be the first time the law has been applied.

The case underlines the abiding sensitivity in Russia around the legacy of World War II, during which more than 26 million Soviet citizens are believed to have perished.