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.

Question: how was he treated in prison?
Self-contained rewrite: how was Ai Weiwei treated in the chinese prison?