A structural engineer renowned for his investigation into the collapse of the World Trade Center towers on 9/11 says a deadly 2013 building collapse in Philadelphia was "an entirely preventable accident."
Najib Abboud testified as an expert witness on Wednesday as part of the civil trial stemming from the June 5, 2013 collapse.
Six people died and another 13 were injured when an unbraced four-story brick wall collapsed on a Salvation Army store.
Abboud said the tragedy was preventable if demolition at an adjacent structure had not resumed that morning.
The legal team representing building owner Richard Basciano and the Salvation Army have blamed incompetent workers for the collapse.
Abboud said his expertise does not allow him to opine on the soundness of demolition methods.