The Central African Republic's crisis was bad when it began last March, with the "Seleka" rebels taking the capital and overthrowing the government, but it is getting much worse. The chaos is giving way to sectarian violence between Muslims and Christians, including in the capital of Bangui. That's where this photo was taken:

A man holds a knife to his throat, claiming that he is looking for Muslims to cut off their heads. (Issouf Sanogo/AFP/Getty Images)

The photo, taken on Sunday, shows a Christian man in Bangui holding a knife to his throat, signaling his desire to cut the throats of Muslims. There's no telling whether he's been successful, but people like him in Bangui certainly have, killing at least nine civilians over the weekend.

Sectarian violence may be senseless, but it does have a certain self-reinforcing logic all its own. The Washington Post's Sudarsan Raghavan watched a mob of Muslim men in Bangui kill a 23-year-old Christian, stabbing him and cutting his throat. Later, in the young victim's neighborhood, as people absorbed the death, one woman declared, "All the Muslims will die in the country." A man yelled, "We have to burn a Muslim and eat him."

Elsewhere in the country, tens of thousands of Muslims are fleeing Christian militias. Of course not all Central Africans, Muslim or Christians, have the slightest interest in killing fellow citizens of the other religion. But all Central Africans do have to worry about being targeted.

The causes of sectarian conflict are extremely complicated in all cases. In the Central African Republic, it does not help that the country has a very recent history of political violence. This photo, from December, when the fighting was political rather than sectarian, shows a young man with the Anti-Balaka militia holding a knife to his throat to show his intention to kill members of the Seleka rebel group:

A fighter with Anti-Balaka, the militia opposed to the Seleka rebel group, puts a knife to his throat to show what would do to Seleka members. (Ivan Lieman/AFP/Getty Images)

These photos are just two moments in time and do not capture the full complexity of the country's violence, of course. But the parallels between them are a reminder of the speed with which political violence can become sectarian violence, and the ease with which armed young men, unrestricted by the state or by society, can replace one sort of target with another.