As “Mr. Werner,” Mr. Denisultanov-Kurmakayev had lived for more than a year in Kiev, mingling with politicians and anti-Russian activists before the shooting on June 1.

Image Artur Denisultanov-Kurmakayev posed as a reporter from the French newspaper Le Monde but was in fact a Chechen assassin, according to the Ukrainian authorities.

The cover was good but not flawless, Ms. Okuyeva said in an interview, her first with a foreign news organization since the attempted murder. She was accompanied by two bodyguards who were on high alert throughout the interview.

One indication that Mr. Denisultanov-Kurmakayev was not who he said he was: He always carried a notebook but never bothered to write in it, Ms. Okuyeva said. He wore an expensive-looking suit, also a hint that something may have been amiss.

There was nothing unusual in the request for an interview, however. “The press often asked for interviews,” Ms. Okuyeva said. “The media loves to write about us.”

Ms. Okuyeva and Mr. Osmayev, both ethnic Chechens, are well known in Ukraine. In 2012, the Russian government accused Mr. Osmayev of plotting to kill Vladimir V. Putin, who was then the prime minister. Mr. Osmayev was arrested in Ukraine, but his extradition to Russia was blocked by the European Court of Human Rights.

After the Ukrainian revolution in 2014, he was released, and he and his wife joined a unit of ethnic Chechens fighting in the war in the east, the Dzhokhar Dudayev battalion. Mr. Osmayev has been its commander since 2015. Ms. Okuyeva served as a sniper, wearing a camouflaged head scarf at the front.