A breach of construction safety regulations has been identified by Czech authorities as the likely cause of the building collapse in Prague, which killed four workers last week. The building in central Prague collapsed when it was undergoing reconstruction work, trapping workers in the rubble. The workers have been identified as two Bulgarians, one Ukrainian and a fourth man, who is believed to be also Ukrainian. If the construction company responsible for refurbishment is found to be liable, the company could face heavy fines, or even prison sentences ranging from 3 to 10 years.