Complex sentence: His disappearance gave rise to many theories as to what had happened to him and where his body was hidden, one of which states that his body is buried underneath Giants Stadium in New Jersey, although no evidence has been found.
Split into simpler sentences: His disappearance gave rise to many theories as to what had happened to him and where his body was hidden. There is one theory that his body is buried underneath Giants Stadium in New Jersey, although no evidence has been found.