The Federal Bureau of Investigation arrested four animal-rights activists late last week in connection with the harassment of University of California scientists in incidents in 2007 and 2008, the agency said in a news release.

According to a charging document, the four suspects “used force, violence, or threats to interfere with the operation of the University of California in violation of the Animal Enterprise Terrorism Act,” the FBI said.

The four are accused, together or individually, of taking part in a demonstration outside the home of a University of California at Berkleley researcher on October 21, 2007; in a series of demonstrations on January 27, 2008, outside the residences of several Berkeley researchers; and in an incident on February 24, 2008, in which half a dozen masked protesters banged on the door of the home of a University of California at Santa Cruz researcher and struck her husband when he came to the door.

Three of the suspects also are accused of producing fliers, found at a Santa Cruz coffee shop last July, that denounced 13 university employees as animal abusers and listed their names and addresses. Two university researchers, including one who was listed on the fliers, later suffered firebomb attacks at their homes. None of the suspects arrested last week are accused in the firebombings, which remain under investigation. Those attacks sparked widespread anger and anxiety among university researchers across the country, and helped lead to passage of a California law that gives law-enforcement officers additional tools to protect researchers from intimidation.

Campus officials in Berkeley and Santa Cruz praised the arrests and the FBI investigation in statements quoted by the Los Angeles Times.

Dan Mogulof, a spokesman for Berkeley, said university researchers had been harassed at their homes, laboratories, and elsewhere in 158 incidents since August 2007. “We find that intolerable and abhorrent,” he told the Times. “We hope that the arrest of these suspects will send a clear and powerful signal to extremists who continue to engage in dangerous and illegal actions against university researchers.” —Charles Huckabee