German police said they were investigating sudden, unexplained illnesses suffered by a Russian opposition activist and a Russian journalist who attended a conference in Berlin in April.
In statement to RFE/RL, Berlin state police confirmed earlier reporting by the German newspaper Die Welt that police were looking into the illnesses that were reported by two individuals around the time of the conference, which was held April 29-30.
SEE ALSO: Atlantic Council Confirms Herbst Fell Ill Amid Possible Russian-Linked PoisoningsThe conference was organized by Mikhail Khodorkovsky, a former Russian oligarch who was imprisoned in Russia for years. He now lives outside of Russia and funds a number of initiatives opposed to the government of Russian President Vladimir Putin.
A “case has been opened” and “the investigation is ongoing,” Berlin police said in a statement on May 21. No further details were released.
Earlier this week, the Russian news outlet Agentstvo reported that one of the people who fell ill was a Russian journalist who was treated at Berlin’s Charite hospital. That hospital was known for, among other things, its involvement in investigating the nerve-agent poisoning of opposition activist Aleksei Navalny in 2020.
The European Union and Britain later targeted six top Russian officials and a state scientific research center for the poisoning.
The other person who reportedly fell ill was Natalia Arno, a U.S.-based activist who heads an organization called the Free Russia Foundation.
In a Facebook post, Arno, who said she traveled to Prague after Berlin, described her problems as "sharp pain" and "numbness.” She has since recovered.
Agentsvo said the FBI had taken blood samples from Arno and was investigating her illness.
Separately, the Washington-based think tank Atlantic Council confirmed that one of its senior staffers, former Ambassador John Herbst, had experienced symptoms that it said were consistent with poisoning two years ago.
Herbst, who served as U.S. ambassador in Ukraine and Uzbekistan, fell ill in April 2021 and experienced symptoms "that could have been consistent with poisoning, including elevated levels of toxins in his blood."
Doctors treated Herbst "effectively at the time but could not definitively conclude there was poisoning involved,” the organization said.
The Atlantic Council also said federal agents had taken blood samples from Herbst, but lab results did not find anything toxic.