Complex sentence: It further argues that the Israeli intelligence service, Mossad, was involved in the attacks, warning Israelis to avoid the Twin Towers in the preceding days, claiming that only one Israeli died in the attacks.
Split into simpler sentences: It further argues that the Israeli intelligence service, Mossad, was involved in the attacks, warning Israelis to avoid the Twin Towers in the preceding days. This is supported by the claim that only one Israeli died in the attacks.