German authorities are investigating the possible poisoning of two Russian exiles who attended a conference in Berlin last month organized by Kremlin critic Mikhail Khodorkovsky. The investigation is being handled by the state security unit, which specializes in cases related to terrorism or politically motivated crimes. The probe was launched after two women reported symptoms that suggested possible poisoning. One of the participants, a journalist who had recently left Russia, experienced unspecified symptoms during the event and went to the Charite University Hospital in Berlin. The second participant, Natalia Arno, director of the NGO Free Russia Foundation in the US, experienced symptoms after attending the Berlin meeting of dissidents and discovering that her hotel room had been opened in Prague. Several poison attacks have been carried out against Kremlin opponents in recent years, including the poisoning of Alexey Navalny with Novichok, a Soviet-made nerve agent.