Chilling footage shows a killer dancing and celebrating minutes after beating his love rival to death in a row over a cup of TEA.Gavin Casey, 31, attacked Christopher Messenger, 36, after flying into a jealous rage because his ex-partner offered to make him a cuppa. Casey smashed Mr Messenger, who was recovering from a car accident, with bottles and stamped on his face before dropping a TV on him. CCTV showed Casey dancing maniacally in a car park after the attack on February 9, while he was heard laughing and shouting: "I've killed him."