After days of speculation surrounding the sudden disappearance of renowned Chinese avant-garde artist Ai Weiwei, China's foreign ministry has confirmed that they've detained Ai for suspected "economic crimes," insisting that the investigation "has nothing to do with human rights or freedom of expression." Ai is a frequent critic of the Chinese government, but "economic crimes" seems like an odd charge to level at a pro-democracy activist.

Chinese officials have not elaborated on the charges, but analysts have jumped in to fill the void. The Financial Times explains that, in China, the "catch-all charge" of economic crimes encompasses offenses ranging from tax evasion to fraud, and is "often used to discredit and imprison advocates of human rights and free speech in China." The Associated Press notes activists have faced vague charges of economic crimes in the past: New York Times news assistant Zhao Yan was sentenced to three years in prison in 2007 for financial fraud and lawyer Xu Zhiyong was detained for alleged tax evasion in 2009 but later released.

Ai told the FT last January that state security agents had pored over his bank accounts, and police more recently raided Ai's studio after detaining him. The formal search and seizure, states Jereme Cohen at NYU's Asia Law Institute, indicates that the police may be planning a criminal prosecution instead of the "informal detention and quick release" that they often apply to dissidents. The BBC adds that the economic crimes charge "may signal that China's authorities will seek to characterise [Weiwei] as a common criminal, rather than a political prisoner."

Ultimately, however, Slate's Tom Scocca argues that "the authorities have decided that Ai Weiwei is unlawful--the particular law doesn't seem to matter."