Federal security agents have searched the Moscow studios of Russia's renowned Ekho Moskvy radio, and summoned the station’s web editor for questioning.
The Federal Security Service said on July 5 that agents had seized e-mail correspondence and other information connected to a prominent analyst and Kremlin critic who fled Russia earlier this year.
It said the investigation concerned possibly incitement of ethnic hatred and undermining Russia's territorial integrity, both of which considered crimes.
The station's editor in chief, Aleksei Venediktov, confirmed the investigation in a message posted to Twitter.
That analyst, Andrei Piontkovsky, left the country after some Russian lawmakers demanded a criminal investigation into an article he wrote in January about the turbulent North Caucasus region.
Some officials alleged the article incited ethnic hatred and undermined Russia's territorial integrity, which is considered a crime.
Owned by a Kremlin-controlled natural gas company, Ekho Moskvy is one of the few remaining independent media outlets in Russia.
It has managed to avoid being targeted for criminal investigations, which are often used in Russia to silence media.