ST. PETERSBURG — A criminal case against the art group Voina over a stunt where they overturned police cars has been dropped by investigators.

Voina artists Oleg Vorotnikov and Leonid Nikolayev were arrested in Moscow in November last year and charged with criminal mischief motivated by hatred of the social group “police,” and spent three months in a pretrial prison in St. Petersburg. They were released on bail partly paid for by British graffiti artist Banksy, who donated 80,000 pounds to the group in February.

According to the ruling, a scan of which was posted on Voina’s web site last week, the artists’ actions “do not contain signs of crimes governed by Article 213 [motivated by hatred of a specific social group].”

As a result, Nikolayev no longer faces any charges and the group will get back their bail money. Voina has already said that the group will use the money to help other political prisoners.

But Vorotnikov and his wife Natalya Sokol remain under investigation for their part in a Strategy 31 rally on March 31. They have been charged with assaulting a police officer and insulting a police officer, respectively.