A roadside bomb killed four Iraqi civilians and injured one other in eastern Baghdad on Sunday, while police said they were searching for gunmen who kidnapped about 50 Shi'ite travelers on a highway south of the capital the night before. The explosion, which hit just after 8:00 a.m. (0500 GMT), had apparently targeted but missed an Iraqi police patrol, said police Cap. Mohammed Abdul-Ghani. An earlier explosion in the capital was aimed at a US military convoy, but there were no reports of damage or injuries, he said. Police patrols were looking for Sunni gunmen who ambushed a convoy of minibuses at a fake checkpoint on the dangerous highway, killing 10 Shi'ite passengers and kidnapping about 50, said a police officer who asked that his name not be used because he wasn't authorized to speak to media.