New testing on the type of ammunition used in the 1963 assassination of President John F. Kennedy raises questions about whether Lee Harvey Oswald acted alone, according to a study by researchers at Texas A&M University.

Lead researcher Cliff Spiegelman stressed, however, that the research doesn't necessarily support conspiracy theorists who for decades have doubted Oswald was the lone gunman.

"We're not saying there was a conspiracy. All we're saying is the evidence that was presented as a slam dunk for a single shooter is not a slam dunk," said Spiegelman, a Texas A&M statistics professor and an expert in bullet-lead analysis.

STORY HIGHLIGHTS

• Study doubts prior finding that fragments could only have come from two bullets
• Texas A&M researcher: "We're not saying there was a conspiracy"
• Conspiracy supporters say it helps case that Lee Harvey Oswald didn't act alone
• Museum curator: The study "can't answer anything about the assassination"