Lubbock, Texas ? A world-renowned plague researcher was cleared Monday of the most serious charges he faced related to a bioterrorism scare triggered when he reported plague samples missing from his Texas Tech University lab.

Dr. Thomas Butler, 62, was convicted of 47 charges, but most of them stemmed from an embezzlement and fraud investigation entirely separate from the plague scare.

The jury acquitted Butler of 22 charges accusing him of smuggling and illegally transporting the potentially deadly germ, as well as lying to federal agents.

The charges stemmed from his report to police Jan. 14 that 30 vials of the potentially deadly plague bacteria were missing from his lab. In a statement written later, Butler said he accidentally destroyed the samples. However, during his trial he testified that he had no clear memory of destroying the vials but that they could have been destroyed during his cleanup of an accident in January.

No sentencing date was set.

Texas Tech has begun steps to dismiss Butler.