US authorities in Baghdad have received five severed fingers belonging to four Americans and an Austrian who were taken hostage more than a year ago in Iraq , US officials said Wednesday.

The FBI is investigating the grisly development, and the families of the five kidnapped contractors have been notified, American officials said on condition of anonymity because they weren't authorized to discuss the case publicly.

MSG. Peter Black from Smiths Station, AL, of 3rd Brigade Combat team, 3rd Infantry Division listens to an Iraqi woman during a patrol at Al-leg area about 60 kilometers (40 miles) south of Baghdad, Iraq, on Tuesday, March 11, 2008. [Agencies]