Complex sentence: The next day Marita Covarrubias leads an investigation of U.N. troops of the area, and runs into Alex Krycek, who has caught Dmitri, one of the boys, who is the sole survivor of the previous night's events.
Split into simpler sentences: The next day, Marita Covarrubias leads an investigation of U.N. troops of the area. She runs into Alex Krycek, who has caught Dmitri, one of the boys, the sole survivor of the previous night's events.