MARYLAND - A panel of experts began a review Thursday of the techniques used by the F.B.I. to identify the creator of the deadly anthrax letters in 2001.

The panel is expected to take a year-and-a-half to study the process that led the F.B.I. to their primary suspect, Fort Detrick scientist Bruce Ivins.

Skeptics have questioned the F.B.I.'s work in the case.

The study will focus on F.B.I. research and not whether Ivins actually sent the letters.