The AP has reported that Senate Judiciary Committee chairman Sen. Patrick Leahy (D-Vt.) expressed skepticism over the FBI’s contention that Bruce Ivins acted alone in the 2001 anthrax attacks.

During a hearing on the matter in front of his committee today, Leahy, who was a target of the deadly attacks, told FBI Director Robert Mueller that he doesn’t think Ivins was the only person involved.

“I believe there are others involved, either as accessories before or accessories after the fact. I believe that there are others out there, I believe there are others who could be charged with murder. I just want you to know how I feel about it, as one of the people who was aimed at in the attack.”

Ivins committed suicide in late July. The FBI has maintained that Ivins is their only suspect. The National Academy of Sciences will undertake a review of the FBI’s investigation, which could take up to 18 months to complete.