Complex sentence: His Walther pistol was borrowed and used by Volodia Shakhurin, son of the Aviation Minister, to kill himself and Nina Umanskaia, daughter of the Soviet ambassador to Mexico, when Nina refused Volodia's request that she stay in Moscow.
Split into simpler sentences: His Walther pistol was borrowed and used by Volodia Shakhurin, son of the Aviation Minister. Volodia killed himself and Nina Umanskaia, daughter of the Soviet ambassador to Mexico, when Nina refused Volodia's request that she stay in Moscow.