A letter bomb was sent to a German regional leader Wednesday in the eighth such attack in the southern state of Bavaria, authorities said. A secretary became suspicious when an unmarked package arrived at the office of the regional president of the Unterfranken region of the state, Paul Beinhofer, and alerted police. The bomb did not detonate and no one was injured. State prosecutors said the explosive appeared to resemble those used in a series of letter bombs sent to officials in Bavaria since April, particularly because a majority of the addressees came from the same part of the state. The first six packages were sent to regional politicians from the center-left Social Democrats and the conservative Christian Social Union. Although police have DNA traces from the suspected perpetrator and have conducted widespread genetic testing in the region, they have few leads.