Hundreds of people have attended a mass in the southern Polish city of Katowice to remember the victims killed and injured when the roof of an exhibition hall collapsed. More than 60 people were killed when the roof of the building collapsed last Saturday in one of the country’s worst disasters in recent years.Hundreds of people were attending a racing pigeon event at the time. Initial reports suggested the weight of snow on the roof had caused the accident. However, a lawyer for the company that runs the hall said the snow had been cleared. The designer of the building is being questioned by police in hospital after trying to commit suicide two days after the disaster. Officials, meanwhile, have warned that more bodies may be found in the twisted metal of the trade hall. The court conducting the inquiry has heard that several emergency exits had been blocked, although it remains unknown if they were locked, or had been closed off by the heavy snowfall.