BEIJING (REUTERS).- Chinese dissident artist Ai Weiwei, whose disappearance in April caused an international outcry, endured intense psychological pressure during 81 days in secretive detention and still faces the threat of prison for alleged subversion, a source familiar with the events told Reuters. In the first broad account of Ai’s treatment in detention since he was released in June, the source, who declined to be identified fearing retribution, said the 54-year-old artist was interrogated more than 50 times by police, while he was held in two secret locations. The questioning focussed on his purported role in the planned Arab-inspired “Jasmine Revolution” protests in China in February and his writings that could constitute subversion, said the source. That account runs counter to the Chinese government’s repeated statements that Ai’s detention was based on alleged economic crimes. “What you’re doing is illegal,” Ai told police officers at one