Conversation so far:
what is ai weiwei  release referring to?
On 22 June 2011, the Chinese authorities released Ai from jail after almost three months' detention on charges of tax evasion.
what evidence did they have?
had allegedly evaded taxes and intentionally destroyed accounting documents.
how was he treated in prison?
his sister gave some details about his detention condition to the press, explaining that he was subjected to a kind of psychological torture.

Question: what did they do to him?
Self-contained rewrite: what did the Chinese authorities do to Ai Weiwei?