A renowned 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 (search) lab.

Thomas Butler (search) was convicted of 47 charges, but most stemmed from an investigation entirely separate from the plague (search) 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.

Butler, 62, appeared stunned as the verdicts were read after two days of deliberations. He closed his eyes, shook his head and fought back tears. After the jury left the courtroom, Butler's wife and son hugged him tightly for several seconds.

The charges stemmed from his report to police Jan. 14 that 30 vials of the potentially deadly plague bacteria were missing from his lab. FBI agents rushed to Lubbock to investigate the scare, and President Bush was briefed about the incident.

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.

Butler declined to comment after the verdict.

The jury of nine men and three women also cleared him of smuggling plague samples into the United States in April 2002 and illegally transporting them to federal facilities.

"We are pleased that Tom was found not guilty of lying to the FBI. We are particularly pleased the jury found him not guilty of perpetuating a hoax regarding his report of the missing plague vials," defense lawyer Chuck Meadows said.

Prosecutor Bob Webster said Butler's misdeeds were troubling: "It remains a real tragedy that a researcher who had so much to give to this country could get so far off the track."

Butler was found guilty of 44 theft, embezzlement, fraud, and mail and wire fraud charges pertaining to shadow contracts prosecutors claimed he had illegally negotiated with pharmaceutical companies with which he also had clinical studies contracts. He was acquitted of 10 similar charges.

Those 54 charges were part of an indictment alleging Butler received $320,675 from two pharmaceutical companies to conduct clinical trials on drugs to treat Type 2 diabetes and severe sepsis, an often-fatal infection of the bloodstream, without Texas Tech's knowledge.

The companies paid him "amounts separate from and above" payments to the university's health science center for other clinical studies, the indictment said.

The jury also found Butler guilty of making a false statement on a Fed Ex package that contained plague samples he sent to Tanzania and their unauthorized export to the African country. Butler had marked the package "laboratory materials."

Butler faces up to 240 years in prison on the 47 convictions, but the punishment will be far less under federal sentencing guidelines. He also faces fines up to $11.7 million. No sentencing date was set.

Five jurors declined to comment as they left court.

In the weeks leading to the trial, Butler turned down a plea agreement that would have resulted in a six-month prison term and an $800,000 fine, said Dr. William Greenough, a longtime colleague and a professor of medicine at Johns Hopkins University School of Medicine in Baltimore.

Texas Tech has begun steps to dismiss Butler, but many in the scientific community have come out in his defense.

Leading scientific organizations have expressed concern about the criminal case against Butler and its effect on infectious disease research. Four Nobel laureates said in an open letter that Butler had been "subjected to unfair and disproportionate treatment" and that prosecuting his case "is having a negative impact on the future of research in this crucial national-security-related field."