Reuters: Nemtsov's last note shows he was on trail of Russian troops dying in Ukraine

It may have been the last note Boris Nemtsov ever wrote, a hurried scrawl in blue pen on a plain white sheet of A4 paper.

A day before he was shot dead near the Kremlin last week, the Russian opposition figure and his close aide Olga Shorina were discussing a sensitive investigation he was preparing into Moscow's backing for separatist fighters in eastern Ukraine, Censor.NET reports citing Reuters.

Fearing their office was bugged by state intelligence, Nemtsov resorted to scribbling.

"Some paratroopers from Ivanovo have got in touch with me. 17 killed, they didn't give them their money, but for now they are frightened to talk," said the note, shown to Reuters by Shorina.

"He did not want to say anything, just in case. He did not want to utter it out loud, which is why he wrote it down for me," she said.

It was not possible to independently confirm the authenticity of the handwritten note.