The roof of the FC Twente stadium in Enschede, which collapsed in July killing two men and injuring 12, was unstable, according to a preliminary report by the safety inspectorate and quoted by NOS news.

The dismantling of the old roof had been started before the new roof had been fully stabilised, says the report. This caused one end of the stadium to collapse sending part of the tribune crashing down.
The stadium is currently being expanded with an extra seating ring and the inspectorate wants to find out why so many people were in the stadium when the accident happened. It will be looking at whether this was because of time pressure.
The final report is expected in April 2012.