Eight University of Wisconsin-Madison scientists are included on a list of people allegedly compiled by a group of animal rights extremists accused of sending threatening letters booby-trapped with razor blades.

The UW researchers are affiliated with the Wisconsin Regional Primate Research Center.

UW Police Chief Susan Riseling said today that professors received a warning Monday and a first envelope on Monday afternoon. Three more envelopes arrived on Tuesday.

A researcher affiliated with the primate center says some of the envelopes contained razor blades.

Virginia Hinshaw, dean of the UW Graduate School and senior research officer responded to the threatening letters sent by animal rights extremists.

"The University community is appalled by this illegal campaign. The mailings are an ill-conceived attempt to hinder the research environment of UW-Madison and other prominent universities."

"Such acts will not interfere with the University's work to fulfill its research mission. We are advising University employees to be aware of this problem and use extra caution with any suspicious letters they receive."

Hinshaw continued, "This is a serious criminal matter now under investigation. I am referring any further inquiries to the University Police."

Police in Massachusetts said a note from the organization calling itself the "Justice Department" was intercepted during the weekend by a group that monitors such extremists. The note contained a list of about 80 researchers scattered across the country who do work with primates.

Las Vegas FBI officials have confirmed a portion of the letters were mailed from the city of Las Vegas.