A man who climbed under the roof of the Dortmund stadium during Germany’s European Championship round of 16 match on Saturday was masked and carrying a large rucksack, according to video footage. The video, published by the website of English newspaper Daily Mail, shows the man being arrested by police after the match against Denmark. Officers announced that the man was a 21-year-old from nearby Osnabrück. Police said there had been no danger to spectators. A helicopter was used to illuminate the stadium roof as part of the bid to seize him once the majority of fans had left following Germany’…