A mysterious cyber-threat that originated from outside the U.S. and targeted USDA offices in five states—as well as several college campuses—indicates that someone out there is aware of USDA organization and facilities. The threats were taken seriously enough that the FBI visited offices around the country with bomb-sniffing dogs, according to one Denver news source.

Various newspapers said the offices closed covered seven USDA agencies in five states, including USDA’s sprawling agricultural research center and library in Beltsville, Md.; the Animal and Plant Health Inspection Service (APHIS) on North Carolina State’s Centennial Campus; the Food Safety Inspection Service; the Forest Service; the Natural Resources Conservation Service; the Office of the Inspector General and USDA departmental management.

In an email to employees, Agriculture Secretary Tom Vilsack said USDA closed the offices “due to the serious nature of these threats.” He did not characterize the threats or say how they were received, but asked employees to be aware of their surroundings and report any suspicious activity. Most of the offices reopened Tuesday (the threat occurred Monday), but two did not reopen until yesterday after security enhancements.

Faculty members at North Carolina State, Virginia Tech and the College of William and Mary also received the identical emailed threat. Virginia Tech’s student newspaper, the Collegiate Times, reported that at least four separate accounts received emails with “Warning” as the subject line. The sender used at least four names, including Rex King, Robert Birdman, Jack Bauer, and John Grind.

The email said: “I am here to inform [sic] that in the next couple of days I will break into the campus and will kill as many people as I can until the police arrives [sic].”