Irish police have arrested three more people in connection with a fatal arson attack on a house in Waterford. Gardaí confirmed that the new group comprises one man and two women. The arrests broaden the inquiry into the fire that damaged the property and killed people inside. Police have not released the suspects' names or described the role each is alleged to have played. No specific charges have yet been reported against the three. Detectives are working to establish how the blaze started and who was responsible. Earlier arrests had already been made as police investigated the same incident.