THE SIGNATURE OF A SINGLE BOMBER?

Federal agents have told TIME that they are exploring whether all three Atlanta bombings were committed by the same bombers. According to government sources, some investigators suspect that the Olympic Park, abortion clinic and Otherside lounge bombings involved devices with similarities that could add up to a common signature. The clock timers from each bombing are similar, sources say, as are the types of copper wire used in the fusing mechanisms. Forensic tests reportedly indicate the presence of unusual metal in some components, but further tests must be done to determine whether chemically identical substances are present in all the bombs. Jurisdictional splits are causing bureaucratic competition. The Olympic Park bomb is being tested at the FBI lab in Washington while the clinic and nightclub devices are being examined at the ATF lab in Atlanta.

--By Elaine Shannon