A US district court in Buffalo, New York, last week cleared Steven Kurtz, an art professor at the State University of New York at Buffalo, of criminal charges related to the possession of bacterial cultures.

Four years ago, Kurtz found his wife dead at their home from a heart attack, and police responding to his emergency call discovered lab equipment and cultures there. Kurtz used biological materials to create politically charged art on topics such as government policy on genetically modified crops.

Initially investigated on charges of bioterrorism (see Nature 429, 690; 2004), Kurtz was indicted in 2004 for mail and wire fraud after receiving bacterial samples through the post. The case inspired the 2007 film Strange Culture.

In February, Robert Ferrell, a researcher at the University of Pittsburgh in Pennsylvania who sent the samples to Kurtz, pleaded guilty to mailing an injurious article and was fined $500.