A demonstrator faces riot police officers after the killing of Chokri Belaid in Tunis, Wednesday, Feb. 6, 2013. The Tunisian opposition leader critical of the Islamist-led government an

A demonstrator faces riot police officers after the killing of Chokri Belaid in Tunis, Wednesday, Feb. 6, 2013. The Tunisian opposition leader critical of the Islamist-led government and violence by radical Muslims was shot to death Wednesday — the first political assassination in post-revolutionary Tunisia. The killing is likely to heighten tensions in the North African nation whose path from dictatorship to democracy so far has been seen as a model for the Arab world. (AP Photo/Amine Landoulsi)