Police booked the owner of a hotel that caught fire last week and claimed the lives of seven people for investigation on charges of professional negligence, officials said Monday.The Gyeonggi Nambu Provincial Police booked the owner of the hotel in Bucheon, west of Seoul, and its nominal head, both in their 40s, and imposed a travel ban on both after Thursday's fire killed seven and injured a dozen people.The fire started on the eighth floor of the nine-story hotel. Officials said the fire led to a large number of casualties as the hotel was not equipped with sprinkler systems and smoke spread quickly through narrow corridors.Many died of smoke inhalation, but two victims fell to their deaths after jumping onto a safety air mattress that firefighters installed on the ground. Video footage showed the mattress overturning after one of the two landed on a corner of it.Police have questioned 15 people as witnesses so far, including the survivors of the fire and hotel employees. They plan to investigate h ow the fire started, and what made it spread so fast, leading to many human casualties.Source: Yonhap News Agency