context: Boris and Gleb (baptized Roman and David; killed in 1015) - Russian princes, sons of the Kiev Grand Duke Vladimir Svyatoslavich. In the internecine struggle that broke out in 1015 after the death of their father, they were, according to the official version, killed by their older brother Svyatopolk, who later received the nickname “Cursed” from official historiographers. Boris and Gleb became the first Russian saints, they were canonized in the guise of martyrs, martyrs, making them patrons of the Russian land and "heavenly helpers" of the Russian princes.
question: Who killed the Russian princes Boris and Gleb?
answers.text: older brother Svyatopolk