RIGA, Latvia — At least 47 people died, including three firefighters, after an enormous section of roof collapsed at a Latvian supermarket in the country's capital, emergency medical officials said Friday. The reason for the collapse during shopping rush-hour Thursday was still not known but rescue and police officials said that possible theories include building's design flaws and poor construction work. Pictures from residential buildings overlooking the store showed an enormous crater-like hole in the roof. Building materials were stacked on remaining sections of the roof, where workers were building a garden as part of the Maxima supermarket's original design plan. The Fire and Rescue Service said 40 people were injured, 28 of whom were hospitalized, including 10 firefighters. The service could not say how many people might be trapped under the rubble. Several large construction cranes hauled debris from the hole, where firefighters slowly sifted looking for survivors. Rescue workers periodically turned off all equipment and asked relatives of missing people to call so that they can pinpoint ringing phones, rescue service spokeswoman Viktorija Sembele said. — AP