Science has finally spoken, and the answer is...we'll probably never know who mailed that anthrax in 2001.

Using the available scientific evidence "it is not possible to reach a definitive conclusion" about the source of the anthrax used in the 2001 anthrax letter attacks which killed five people, according to a report issued Tuesday by the National Academy of Sciences.

Science seems to have proven, though, that Bruce Ivins, who was suspected of being the anthrax mailer (and who committed suicide in 2008) did not do the deed.

Paul Kemp, a lawyer who represented Ivins, said that since August 2008, the Justice Department has maintained it had a "smoking gun" in the case against Ivins, citing the flask.

"Their smoking gun just turned into smoke and mirrors," Kemp said of the report. "They said they had a smoking gun that would have convicted him (Ivins) in court and this report shows they didn't."