Complex sentence: He also claimed that Mussolini was inadvertently wounded earlier in the day when Petacci tried to grab the gun of one of the partisans, who killed Petacci and Michele Moretti then shot dead Mussolini.
Split into simpler sentences: He also claimed that Mussolini was inadvertantly wounded earlier in the day when Petacci tried to grab the gun of one of the partisans. The partisan killed Petacci and Michele Moretti then shot dead Mussolini.