An LSU scientist is the lead author of a paper that questions the FBI’s conclusions about the anthrax mailed out 10 years ago in attacks that killed five people and made 17 others sick, according to the New York Times.

In the paper, LSU’s Martin Hugh-Jones argues that chemicals found in the dried anthrax spores, particularly tin, indicate a high degree of manufacturing skill. The FBI’s investigation found that the attack germs were unsophisticated, the New York Times reported.

The Times story says that the new report raises the possibility that Bruce Ivins, the Army biodefense expert identified by the FBI as the culprit, had help in obtaining his germ weapons or was innocent of the crime. Ivins killed himself in 2008, shortly before he was to be arrested.

Hugh-Jones, a world authority on anthrax, and the other scientists make their case in a coming issue of the Journal of Bioterrorism & Biodefense. The scientists say the investigation should be reopened.

Tin is used in antibacterial products. It kills micro-organisms.

The scientists say its presence in the mailed anthrax is surprising and suggests that the germs got a specialized silicon coating, with tin as a chemical catalyst, according to the Times. These coatings are common in the manufacture of drugs and other products.

“It indicates a very special processing, and expertise,” Hugh-Jones told the paper. The deadly germs sent through the mail to news organizations and two U.S. senators, he added, were “far more sophisticated than needed.”

If Hugh-Jones and his colleagues are right, it’s likely that Ivins could not have made the anthrax powder with the equipment he had on hand, the Times story says. That would mean he got the powder from somewhere else or that he wasn’t the perpetrator.

However, other scientists who reviewed the research have said the tin might be random contaminants.