A former employee of Host International was arrested in the slaying of his former boss four months ago at Los Angeles International Airport. Henry Earl Duncan, 20, a former cashier, was booked by Los Angeles police for investigation of murder in the death of night manager Josephine Ilene DeBaun, 28, whose body was found by a fellow worker Nov. 14. Detective Leroy Orozco said Duncan was arrested at his home in the 13900 block of South Central Avenue after warrants were served on him. The victim, the mother of 2-year-old identical twin boys, was assaulted at the Host International restaurant in the Pan American Airlines satellite some time during the night. Duncan was expected to be arraigned today in West Los Angeles Municipal Court on a complaint accusing him of murder, robbery and grand theft.