Complex sentence: Amanda Knox, an American exchange student and flatmate of Kercher, and Knox's then-boyfriend, Raffaele Sollecito, an Italian student, were convicted at the initial stage of a two-level trial process.
Split into simpler sentences: Amanda Knox, an American exchange student and flatmate of Kercher, and Knox's then-boyfriend, Raffaele Sollecito, an Italian student. They were found guilty at the initial stage of a two-level trial process.