"We will...strap you into a monkey restraining device and use industrial pliers to crack your testicles like walnuts." That was the simple message that medical researcher Dr. Donal O'Leary received in October 2011.

UCLA neuroscientist David Jentsch, who conducts research on rodents and primates, received a gruesome package earlier this month: "Bloody, AIDS-tainted razor blades," courtesy "the Justice Department."