Kirov Murder (Activity p. 210)

I find Source 13.6 hard to believe because the speaker seems very disorganized with her evidence, which seems lacking (all her testimonies have been "destroyed"), and it was during a time when Stalin was attacked, so I find it improbable that her last statement is true: "It has been irrefutably proved that the murder of Kirov was organized by Stalin". Source 13.7 also does not present any specific evidence to back up the claims made. However, the thing written in Nikolayev's diary about personal revenge seems pretty clear that he was not doing on account of Stalin's orders, so I think I am leaning towards the theory that Stalin was not involved. I think it is 'certain' that Nikolayev was indeed the murderer since there is no evidence whatsoever against that fact and a substantial amount for it, and judging from what I read in the sources, I think it is highly likely that the biggest motive he had was personal reasons, but probable that the NKVD also encouraged/inspired/aided him in his assassination of Kirov because of their interests in preserving the strong role of the NKVD, etc.