MOSCOW (AP) — Prosecutors on Thursday opened an inquiry into Russia’s top independent TV station over a poll that asked a question about World War II regarded by some as historical sacrilege.

The controversy over the Dozhd station reflects the challenges faced by the few media outlets outside the Kremlin control. It also shows just how divisive history issues can be in today’s Russia.

Dozhd, which broadcasts on the Internet, cable and satellite channels, asked D to avoid the more than 1 million deaths that followed.

President Vladimir Putin’s spokesman, Dmitry Peskov, said Wednesday that the poll crossed a moral “red line,” but may not have been illegal. That didn’t stop prosecutors from opening an inquiry Thursday on whether the station violated the law.

At the same time, Russia’s media oversight agency warned Dozhd that it violated a legal provision that requires the media to respect the public.

Without waiting for the results of the official probe, several top cable and satellite providers cut Dozhd from their packages, a move that Dozhd’s owner, Nataliya Sindeyeva, attributed to pressure from unidentified government officials.

While Dozhd’s reach is small compared to state-controlled nationwide television stations, it has been very popular among the urban middle class that was the driving force behind massive protests in Moscow in 2011-2012 against Putin’s re-election. The station’s eagerness to give the floor to opposition leaders and its critical reporting long has made it a thorn in the Kremlin’s side.

The poll that ran Sunday touched on one of the most tragic pages in the nation’s history, the 872-day Nazi siege of Leningrad that began in September 1941. More than 1 million city residents died, most of starvation, and the city’s resistance has become a major symbol of the country’s suffering and heroism during WW II.

War historians have argued over the years about whether the heavy death toll could have been avoided. But Dozhd’s attempt to thrust the issue into public debate struck a raw nerve and drew a quick and angry response from officials. Some lawmakers in the Kremlin-controlled parliament immediately called for the station’s closure.

“This (poll) is not just immoral, but it is sacrilegious,” said Vladimir Radin, a Communist, who was among a group of lawmakers who sent a letter urging prosecutors to look into the matter. “I would even say it directly violated the law.”

Dozhd quickly retracted the poll from its website and apologized, but that didn’t end the station’s troubles.

“The situation began moving in the following direction: all of a sudden, our partners — cable networks — first started warning us that they are going to disconnect us and then started actually disconnecting us,” Dozhd’s editor, Mikhail Zygar, told The Associated Press.

Both Sindeyeva and Zygar alleged that the networks’ action appeared to have been instigated by the Kremlin, where they said some officials — whom they wouldn’t name — were angry at the station for airing a report about expensive country residences owned by officials and lawmakers.

“The story began last year when we ran a series of investigative reports about property owned by various lawmakers belonging to the (main Kremlin) United Russia party and to functionaries of the presidential administration,” Zygar said.

Copyright 2014 The Associated Press.