Complex sentence: Meyer Lansky, Joe Adonis, and Benny Siegel knew Luthor was the real murderer and was going to get Willi, and they saved him in hopes of bringing Luthor to jail.
Split into simpler sentences: Meyer Lansky, Joe Adonis, and Benny Siegel. They knew Luthor was the real murderer and wanted to get Willi out, in hopes of sending Luthor to jail.