So terror has again struck Russia.
It struck in Vladimir Putin's hometown of St. Petersburg, which, until now, had been immune from the attacks that have plagued Moscow and other cities.
And it struck while Putin was in town, holding talks with Belarusian President Alyaksandr Lukashenka.
At least 14 people are dead, dozens are injured, and a city of 5 million people is traumatized.
And our thoughts go out to the victims, to their families, and to the city of St. Petersburg.
So what happens now?
Will Putin's Kremlin honor the victims by conducting a thorough and transparent investigation?
Or will it exploit this tragedy for its own political advantage, as it did following the Nord-Ost theater siege in 2002 and the Beslan massacre in 2004?
Will it use yesterday's attack to stoke fear, encourage intolerance, and squash dissent, as the ultranationalist Aleksandr Prokhanov suggested on state television?
We'll see soon enough, and history doesn't provide much cause for optimism.
But in many ways, yesterday's tragedy in St. Petersburg also brought out the very best in ordinary Russians.
They assisted the injured and the frail in the chaos immediately following the blast.
With the city's public transportation paralyzed, taxi drivers offered free rides and private drivers mobilized on social media to get stranded commuters near the blast area home safely.
It was a civic outpouring that was inspiring to watch.
And Putin's Kremlin would do very well to take a cue from its own people.