The battle over animal experimentation in Italy took a nasty turn this week when anonymous activists posted fliers showing photos, home addresses, and telephone numbers of scientists involved in animal research at the University of Milan and labeled them as "murderers." The leaflets, which appeared in the night of 6 to 7 January, triggered widespread condemnation in academic and political circles.

The posters targeted physiologist Edgardo D'Angelo, parasitologist Claudio Genchi, pharmacologist Alberto Corsini, and Maura Francolini, a biologist. The texts say they are “guilty” of performing animal experiments; Corsini is said to "have tortured and killed animals for more than 30 years.” His flier ends with his phone number and the suggestion to "call this executioner and tell him what you think of him."

Although the fliers didn't contain a specific call to violence, the implicit threat is unmistakable, Italian scientists say. Pro-Test Italia, an organization that seeks to defend and explain animal research, has likened the campaign to a witch hunt. “It's unacceptable that those who work for the good of science and public health are called murderers by someone who publicly incites violence against them,” says Dario Padovan, a biologist and president of Pro-Test Italia.

Many politicians condemned the new tactic as well. "I wish to express my deepest sympathy and support to the researchers in Milan for the intimidation and threats they suffered," Italy's minister of education, universities and research, Maria Chiara Carrozza, tweeted yesterday. The University of Milan has filed a complaint and the city's police department has started an investigation. “We will strengthen our commitment to the defense of research as a tool to improve knowledge and care for sick people,” Gianluca Vago, the university's rector, told the newspaper Corriere della Sera.

Genchi, one of the targeted scientists, tells ScienceInsider he's not scared, but feels "uneasy" about the paper attack, which he says comes from "uninformed fanatics."

Animal research has been the issue of an intense political debate in Italy. The Italian government is expected to soon approve a bill that would put drastic limitations on animal testing, which has generated an outcry in the scientific community. In December, a row erupted when a 25-year old veterinary student at the University of Bologna posted a defense of animal research on her Facebook page, which triggered a torrent of verbal abuse. The student, Caterina Simonsen, suffers from four genetic diseases; without animal experimentation, she wrote, "I would have died when I was nine." Her story dominated the Italian media for days.

Last April, activists entered an animal facility at the University of Milan, released mice and rabbits, and destroyed experiments.

“I disagree with any violent act against human beings or animals,” Michela Kuan, a biologist and a member of the animal rights group Lega Anti Vivisezione told ScienceInsider when asked for a reaction. But, she added, "there is a lot of manipulation of the facts in the media at this delicate time."

*Correction, 10 January, 10:35 a.m.: Dario Padovan is currently the president of Pro-Test Italia, not the coordinator of Pro-Test Italia's scientific committee, as previously reported. This has been fixed.