Engineer who warned over Bangladesh building held, toll tops 500
* Engineer had said building was unsafe day before accident
* Death toll climbs to 501, scores still missing
* Canada's Loblaw says will add "building integrity" to audits
By Ruma Paul
DHAKA, May 3 (Reuters) - Police investigating the collapse of a Bangladesh factory building that killed more than 500 people have arrested an engineer who warned the day before that the eight-storey complex was unsafe.
The arrest of engineer Adbur Razzak brought to nine the number of people held over the April 24 disaster, which has put the spotlight on the many Western clothing retailers who use Bangladesh as a source of cheap goods.
One firm whose garments were being made in the doomed building, Canada's Loblaw, said on Thursday it would continue to produce clothes in Bangladesh but promised to improve the facilities it uses there.
The death toll from Bangladesh's worst industrial accident rose to 501 on Friday, with the scores of relatives still gathered at the site in a Dhaka suburb clutching photographs of loved ones attesting to the many more still missing.