KATHMANDU A powerful bomb went off outside the house of the daughter of Nepal's prime minister Wednesday and a senior police officer was killed in attacks blamed on an escalating Maoist rebellion, AFP said. Police said they believed the bomb outside Sujata Koirala's house was planted by the Maoists, who have intensified their violence since the royal massacre last month, as a message to her father, Prime Minister Girija Prasad Koirala.