Six Harvard Medical School (HMS) researchers have received threats in the last two days from an animal rights activist group, condemning their non-human, primate-based research.

The medical school affiliates received letters--each with a razor blade enclosed--in which the group, known as Justice Department, threatened to take further action if the researchers did not stop their experiments.

According to the group's Web site, Justice Department plans to send more than 80 similar envelopes to other researchers across the country who they say use vivisection--surgical experimentation on living animals--in their work.

The group included a note in its letter to the targeted researchers, warning them that they have "until autumn of 2000 to quit [the] vivisection industry, or be subjected to violence which is uncomparable [sic] to booby trapped letters."

Among those listed on the group's Web site as potential letter recipients are 11 Harvard affiliates:

Assistant Professor of Neurobiology Richard T. Born; Assistant Professor of Medicine Zheng W. Chen; Professor of Psychology Marc D. Hauser; Assistant Professor of Microbiology and Molecular Genetics Jae U. Jung; Associate Professor of Pathology Andrew A. Lackner; Instructor in Veterinary Medicine David E. Lee-Parritz; Associate Professor of Psychobiology Bertha K. Madras; Professors of Psychobiology William H. Morse and Roger D. Spealman; James T. Wortham, associate director of the New England Regional Primate Research Center; and Associate Professor of Medicine Frederick C. Wang.

HMS officials yesterday would not release the names of those researchers who have already received letters, so it was not known if those six included any of the 11 researchers listed on the Web site.

The medical school's director of public affairs Donald L. Gibbons said yesterday that the investigation will be handled by the FBI. Yesterday, an FBI spokesperson in the Boston office refused to comment on the status of the investigation.