Complex sentence: In November 1973 an envelope containing a lock of hair and a human ear was delivered to a daily newspaper, with a threat of further mutilation unless $3.2 million was paid: This is Paul's ear.
Split into simpler sentences: In November 1973 an envelope containing a lock of hair and a human ear was delivered to a daily newspaper. The demand threatened that Paul would be further mutilated unless $3.2 million was paid: This is Paul's ear.