图为美国警方公布的波士顿爆炸案嫌犯图像。在爆炸发生时，身背背包的两名男子举止可疑。美国媒体称，这是此次爆炸案案情的重大进展。[新华社 张军 摄]
Photos released by the U.S. Federal Bureau of Investigation (FBI) in Boston on April 18, 2013 show one Boston bombing suspect who wears a dark hat. The FBI special agent Richard DesLauriers on Thursday released the photos and video of two suspects of Monday's deadly bombings in Boston, asking for the public's help to identify them. [Zhang Jun/Xinhua]