LONDON - British boxer Carl Froch apologised on Thursday after threatening to "kill" Danish opponent Mikkel Kessler in their IBF super-middleweight bout on Saturday, as the British Boxing Board of Control launched an investigation. Kessler claimed a points victory in the pair's first fight three years ago, but although they have since become friends, Froch launched a verbal attack on his adversary in a pre-fight press briefing. Froch said: "On Saturday night, if I have to, I will kill him. It sounds brutal, it sounds horrible, but this is what it means to me. I'm going to leave it in the ring." However, he took to Twitter to apologise, writing: "I'm sorry if my comments yesterday offended anyone. This fight means so much to me & emotions are running high. See you at the weigh-in." –AFP