Female DNA Discovered on Boston Bomb

Photo: Handout/2013 FBI

At least one of the explosives used in the attack on the Boston Marathon had a woman's DNA on it, The Wall Street Journal reports. It could be nothing: "The genetic material could have come, for example, from a store clerk who handled materials used in the bombs or a stray hair that ended up in the bomb." But just in case, the FBI collected a DNA sample from Tamerlan Tsarnaev's widow Katherine Russell, "the culmination of days of negotiations."