Lusaka, Zambia (CNN)The trail of blood outside the warehouse door was the only immediate sign that a murder had taken place. But CCTV footage seized by police, and seen by CNN, revealed a brutal afternoon of carnage. At midday on Sunday, May 24, three Zambian attackers with iron bars entered the grounds of a Chinese-owned textile warehouse in Lusaka. Police said they were pretending to be potential customers. But the trio did not want to do business. Over the next 17 minutes, the CCTV footage shows, they beat two men and one woman to death in the courtyard, before dragging...