Please translate this bengali into english And explain the words piece by piece please. Thanks. The death toll from the collapse of a Bangladesh factory building has passed 500, officials said, as police investigating the disaster arrested an engineer who warned the day before the tragedy that the eight-storey complex was unsafe. The detention of Abdur Razzak brought to nine the number of people held over the disaster, which has put the spotlight on the many western clothing retailers using the country as a source of cheap goods. Scores of relatives remained at the site in a Dhaka suburb on Friday, clutching photographs of loved ones attesting to the many more still missing, as the number of deaths in the country's worst industrial accident rose to 501. Razzak had been called to Rana Plaza in Savar, 20 miles north of the capital, by its owner when cracks appeared in concrete pillars the day before the accident.