Complex sentence: Although David Jove had suggested throughout the'80's that disgruntled punk rockers were responsible, it was Jove himself who made sure (from his death bed in September 2006) that his friends knew he was the murderer of his friend Ivers.
Split into simpler sentences: Although David Jove had suggested thru the'80's that disgruntled punk rockers were responsible. It was Jove himself who made sure, from his death bed in September 2006, that his friends knew he was the murderer of his friend Ivers.