SAN DIEGO -- A former University of California, San Diego researcher accused of making a series of bomb threats that forced the evacuation of a campus building pleaded not guilty Monday to a federal charge of providing false information.

Timothy Byron Kalka, 50, was arrested Saturday at his San Diego home.

"The government alleges this defendant made numerous threats to the campus, two by phone and one by mail," Assistant U.S. Attorney Mike Skerlos told U.S. Magistrate Judge Barbara L. Major.

The letter was received Wednesday, and around the time a suspicious device was discovered in a campus research building, Kalka placed telephone calls warning that bombs would be set off unless demands from the Animal Liberation Front were met, Skerlos alleged.

Kalka had ample opportunity to advise authorities that his alleged threats were only a hoax. But instead, he caused officials to waste valuable time and resources to protect students, the prosecutor charged.

It took seven hours to determine the suspicious device was harmless, he said.

Defense attorney Jason Sur told the judge that his client had worked for the school for the past eight years.

According to the FBI, Kalka was fired on Nov. 30. The agency did not describe any ties to the animal rights group, and none were mentioned in court.

The judge set bail at $100,000 and ordered Kalka to surrender his passport, have no contact involving UCSD without prior approval and submit to psychological testing.

A preliminary hearing was scheduled for Dec. 20.