Complex sentence: Mustaine claimed that the group returned home because guitarist Young "ran out of heroin", which Young denied, stating that it was Mustaine who wanted to go back to Los Angeles and seek rehabilitation.
Split into simpler sentences: Mustaine claimed that the group returned home because guitarist Young "ran out of heroin". These allegations were later denied by Jeff Young, who stated that it was Mustaine who wanted to go back to Los Angeles and seek rehabilitation.