German police have opened an investigation into the possible poisoning of two Russians living in exile, officials said on Sunday.Russian investigative media outlet Agentstvo reported that two Russian dissidents who attended a meeting in Berlin on April 29 and 30 described feeling ill. The meeting was organized by Kremlin critic and exiled oligarch Mikhail Khodorkovsky.Berlin police officials told news agencies that they were looking into the case. They provided no other details saying the probe was ongoing.