Campus police led the Oscar nominee away from the University of Wisconsin (Uw) in Madison during a protest staged by People for the Ethical Treatment of Animals (Peta) activists on Thursday morning (07Feb13).
Reports suggest Cromwell held up graphic photos depicting the scientific decapitation of a cat named Double Trouble and yelled, "Shame on Uw for mutilating and killing cats!"
Prior to his arrest, the actor said, "The University of Wisconsin may think that grant money matters more than animals' suffering, but the public who unwittingly funds this cruelty demands an end to these hideous experiments.
"My friends at Peta and I will continue to call on Uw-Madison to stop cutting into and killing cats in this useless experiment."
Thursday's protest comes two weeks after Peta officials sent a letter to the Uw Board of Regents describing the abuse of nine other cats in the same laboratory where Double Trouble was killed.
The protesters asked the regents for an immediate end to the cruel experiments but received no response.