Construction experts are carrying out detailed tests at London's Apollo Theatre following the horrifying roof collapse which injured 76 audience members on Thursday evening (19Dec13). Seven people were taken to hospital with serious injuries and dozens more were treated at the scene after a huge chunk of the venue's ceiling fell down during a performance of The Curious Incident of the Dog in the Night-Time. The 112-year-old Grade II listed building was still sealed off on Friday morning (20Dec13) as structural engineers and a surveyor from the local Westminster City Council carried out an assessment to discover what caused the collapse. Heavy storms had battered London during the evening, and there were unconfirmed rumours the venue had been hit by lightning earlier in the day. Local police have ruled out any criminal involvement. Chief Superintendent Paul Rickett, of the Metropolitan Police, says, "(There is) no suggestion at this stage that (the incident) was as a result of a criminal act." A spokesman for Nimax Theatres, which owns the Apollo, said the collapse was "shocking and upsetting".