Many of the test bullets showed the same "chemical composition," and one matched fragments from the assassination bullets, he said.

Hence the title of the group's paper: "Chemical and Forensic Analysis of JFK Assassination Bullet Lots: Is a Second Shooter Possible?" The team was honored by the American Statistical Association with its 2008 Statistics in Chemistry award.

The study doesn't say there were two or more gunmen, only that the single-gunman theory can't be supported by science.