[1] Suffering from terminal cancer, he continued to hold services until 23 June 2024,[2] when Kotelnikov was murdered by Islamic terrorists that attacked and burned down his church, among other targets.

[3] Nikolai Kotelnikov's spiritual mentor was Protoiereus Pyotr Sukhonosov [ru], the rector of the church in Sunzha, who was kidnapped by Arbi Barayev's militants and tortured to death in 1999.

Orthodox residents of Derbent believe that with the arrival of Father Nikolay, the life of Christians in the city has noticeably improved.

[7] Kotelnikov also participated in interreligious conferences in Dagestan, built relationships with representatives of other religions in Derbent, and at the same time abandoned Orthodox missionary activity.

During the Christmas holidays, Nikolai Mikhailovich regularly went to the social rehabilitation centre for minors and handed out sweets to the children.

[12] Initially, the media reported that the terrorists slit the priest's throat, but this was later denied by the Derbent mayor's office press service, which stated that Kotelnikov was shot.

[14] During Nikolai Kotelnikov's lifetime, a sculptural composition "Monument to the Friendship of Three Religions" was erected in Derbent in Mirza Muhammad-Ali Kazem-Bek Lane, depicting an Orthodox priest, Rabbi and Mullah sitting at one table.