One of two men arrested in an anthrax scare in Las Vegas was returned here Tuesday to face probation violation charges.

Larry Wayne Harris, 46, of Lancaster, Ohio, was brought from Las Vegas, where he and another man were arrested Feb. 18 after an FBI informant said they claimed to have deadly anthrax in their possession. Harris is being held at the county jail here.

Charges were dismissed against the two men on Feb. 23 after tests showed the material was a harmless anthrax veterinary vaccine. William Leavitt Jr. was freed, but Harris is accused of violating his probation for a 1995 conviction for illegally ordering bubonic plague bacteria by mail.

His probation barred him from “conducting any experiments with or obtaining any infectious diseases, bacteria or germs except at approved laboratories in conjunction with verified employment,” the prosecutor’s office said.

Attorneys for Harris and Leavitt said the two men are not terrorists but rather scientists planning to use the anthrax vaccine to test an unorthodox disease-killing machine being promoted by the FBI informant.

Harris will appear in U.S. District Court later this week. He could be sentenced to five years.