Angela Merkel recently condemned the alleged poisoning of Russian opposition leader Alexei Navalny:
"It is shocking information about the attempted murder by poison of one of Russia's leading opposition members," said Merkel in a later news conference.
"This means that Alexei Navalny is a victim of a crime," Merkel added. "It was an attempt to silence him. I condemn this in the strongest possible terms on behalf of the entire German government."
The foreign minister of Germany went as far as to threaten sanctions if the allegations are proven:
Germany would be ready to impose diplomatic sanctions against Russia if it concludes that Russian state agencies were behind the poisoning of a critic of President Vladimir Putin, Foreign Minister Heiko Maas said on Friday.
But why would foreign governments care so much about a member of the Russian opposition? In another question I've asked about the somewhat related scandal around the Skripal poisoning and received the following answer:
In fact, one of the tests for a government to be recognized as sovereign is that they reserve for themselves a monopoly on the use of force within their boundaries. Many governments refuse recognition of the various aspirational Palestinian governments precisely because they do not have this. You simply must have this condition to be considered sovereign in your own territory.
Because of this, willfully using violence within the borders of another country without their permission has always been considered a red line. Doing that is simply incompatible with recognition of that government as a sovereign entity.
However in this instance the poisoning happened on Russian territory to a Russian citizen with no ties to foreign countries, so its unclear why the international community expressed a similar level of dissatisfaction.