Chinese authorities originally announced that they were investigating the artist on the grounds of tax evasion, yet it is more likely that he was taken into custody as a result of his criticism of the Chinese Communist Party. China came under extreme pressure from all around the world once word got out about Ai Weiwei’s abduction.
Phelim Kine, an Asia researcher for Human Rights Watch, said in an e-mail to the NY Times,
“Without the wave of international support for Ai and the popular expressions of dismay and disgust about the circumstances of his disappearance and detention, it’s highly unlikely the Chinese government would have released him. The public announcement of his release signals that the Chinese government has had to respond to this pressure and that the cost-benefit ratio of continuing to detain him was no longer tenable.”