Complex sentence: There were negotiations to release him and his co-prisoner, Japanese journalist Kenji Goto, but Goto was beheaded and al-Kasasbeh was burned to death while he was locked inside a cage.
Split into simpler sentences: There were negotiations to release him and his co-prisoner, Japanese journalist Kenji Goto. However, Goto was beheaded and al-Kasasbeh was burned to death while he was locked inside a cage.