Pictures of a woman brandishing a child's severed head in the centre of Moscow made headlines around the world on 29 February. But the gruesome incident went completely unreported on Russia's main TV channels.
The story appears to have broken at around midday Moscow time, and was quickly picked up by a number of Russian media outlets, including the pro-Kremlin news channel LifeNews.
But as the hours came and went, the main terrestrial TV channels continued to ignore it.
Viewers of the evening news bulletins saw reports about the aftermath of a recent mine disaster, the migration crisis in Europe and Leonardo DiCaprio's triumph at the Oscars.
But they neither saw nor heard anything about the horrific scenes on the streets of the capital.
A report by liberal website RBK quoted two unnamed employees at national TV channels as saying broadcasters had received a "recommendation" not to cover the story, apparently because of concerns about inflaming ethnic tensions.
The woman, who was later arrested, is from the Central Asian republic of Uzbekistan. She also appears to have been shouting "Allahu Akbar" (an Islamic phrase meaning "God is great").
Nationalist activists on social media have been quick to try to make political capital out of the incident.
Presidential spokesman Dmitry Peskov denied the Kremlin told the TV channels not to cover the story, but he sympathised with their response to it.
"It seems to me that one can only show solidarity with this decision, because it was too horrific to show on television," he was quoted as saying by Interfax.
But many social media users reacted with scorn and derision.
In particular, they contrasted the current silence with the evident relish Russian TV has shown in covering crimes alleged to have been committed by immigrants in Europe.
Some also recalled the way Russian state TV has bombarded viewers with fake atrocity stories in Ukraine.
"The non-existent crucified boy in Ukraine created more of a stir in the news in Russia than the real severed head of a child in the centre of Moscow," musician Mikhail Yezhov tweeted (in Russian).
Russian TV has a track record of ignoring or downplaying inconvenient or sensitive stories. But this is certainly one of the most striking examples of this phenomenon.