(This Aug. 26 story has been corrected fix the first name of Alexander Litvinenko in paragraph 6)
By Thomas Escritt
BERLIN (Reuters) - Despite the murders of four of her colleagues for their reporting, Russian journalist Elena Kostyuchenko never considered she had been poisoned when she fell ill on a train to Berlin.
"When you work as an investigative reporter in Russia you are always careful," she told Reuters. "You have lots of protocols you're following all the time. But when I found myself in Europe I totally forgot all these security measures."
German prosecutors are investigating whether Kostyuchenko, who is now living in hiding, was the victim of an attempted murder when she became ill last October.
Her symptoms started with disorientation and stomach ache on the train journey from Munich to Berlin and persisted for several weeks. By the time she realised she may have been poisoned, it was too late to identify any toxins.
"I had to take off my rings because my fingers looked like sausages," she said, describing the swelling that was among her symptoms. Months later, she is still exhausted and only able to work three hours a day.
Enemies of Russian President Vladimir Putin living abroad have been poisoned in the past, including former secret agents Sergei Skripal, who survived, and Alexander Litvinenko, who did not. A former Chechen rebel died in Berlin in what a German court said was a Russian state assassination.
The Kremlin denies involvement with these killings.
"That fitted Putin's narrative, that we can't forgive traitors," Kostyuchenko said. "But I was never working with secret services... Somehow I was thinking that in Europe, I'm safe."
At a time when European Union capitals are seen as potential safe havens by Russian activists and reporters who consider themselves at risk at home, the possibility that they too might be targeted abroad amounts to a chilling step change.
"When I found myself in Europe, I totally forgot about security measures, like when I discussed my trip to Munich I used Facebook Messenger," said Kostyuchenko, a foreign correspondent who exposed alleged Russian war crimes in Ukraine.
When doctors told her she had likely been poisoned her initial reaction was to laugh.
She was one of three Russian independent woman journalists who were apparently poisoned while abroad in a similar period. All three suffered similar symptoms.
"We can confirm that an investigation into the attempted murder of Elena Kostyuchenko is pending," a spokesperson for Berlin prosecutors said on Friday.
(Reporting by Thomas Escritt; Editing by Mike Harrison)